building a weekend toy / engine to bracket race, not transportation

Grumpy

The Grumpy Grease Monkey mechanical engineer.
Staff member
hey grumpyvette, Ive read a bunch of these threads and most of them were heavily slanted toward building street/strip performance engines,
that run on high test pump gas, that's fine and I understand why.
but, what would you build on a semi -reasonable budget,
too put in a weekend toy / engine too bracket race,
not use for transportation, in some smaller lighter car like a A.C. COBRA clone , T-bucket, or VEGA, ?

well if your on a budget and want serious power you'll rather obviously need to look over your local race tracks rule book if you intend to run in a set class....
I've always promoted the idea that building any engine for increased engine durability and consistency is more important than squeezing the last possible potential peak horse power out of any engine.

you want too keep the track tech guys reasonably happy because youll be back week after week....I always found that was a huge P.I.T.A. to go through tech, so keep things simple, and personally Id rather just deal with the basic safety rules and build a car for a bracket or time range to allow you a whole lot more latitude, in what you build, and race.
so the first basic step is to get a copy of that local tracks safety rules and,
Id go talk to the guys over several week-ends,
who currently have cars at that track,
similar to what you might want too race!
I think most of us have run into a great many similar choices, between buying tools and auto parts,
its all a learning process, you want too simply want to mentally take a step back, take a deep breath or two,
and start testing to find out whats working correctly,in your current combo,
whats not working up to your expectations,and if its not meeting your goals, logically calculate what should change,
and then calculate what can be adjusted or if necessary parts that can be logically replaced, and re-tested,
if that required too improve the performance.
don,t make the all too common mistake of thinking adding horsepower is the only route to improved performance.
suspension mods, better shocks, better brakes, a stiffer frame, larger diameter and wider tires, and drive train gearing and removing weight,
and correctly setting up the cars chassis to more effectively apply weight transfer ratios,
swapping to lower weight parts,or stronger , or more durable parts, use of stronger drive train components, better matched gear ratios, all help
its simply the result of a limited budget ,in most cases,
and most of us make a few mistakes ,
but as long as you keep the goal of building the car in mind you'll do ok.
after you gain experience there's both engineering and art involved in the process,
you'll generally start with a goal, you've envisioned for your car, reality and physics will provide some of the limitations, you'll be limited to a budget and at times by your access too tools and limited by your skills and knowledge, youll generally start,by simply making a very detailed list of the components you want too use ,to upgrade and modify the car to gain the performance and look of the car, and once you have that list of components, and being forced by going back through that detailed, list and doing the required math too verify you have selected the correct matching parts, and when you find you have to change a few components you go back, change the list and again revue the math, most of us start out without the required knowledge to accurately match parts and your goal.
yet this process forces you to do some research into what you can reasonably accomplish with the tools and skills you have and the realization that you may need to acquire both skills and more tools as you proceed.
its almost always a good idea to post the city and state you live in, and don,t be afraid to ask questions or post pictures, as there,s at least some chance someone reading about your problem, or question, that has skills and a desire to help might read these posts that lives near you!:thumbsup:
you might luck out and find a helpful mentor within easy driving range willing to help you out or at least get tips on local knowledgeable shops that work on similar cars are reasonable hourly rates, and what dealerships , repair shops, or machine shops in your area, to AVOID LIKE THE PLAGUE:thumbsup:
even weekend bracket,low budget racings never going to be dirt cheap or easy,
but it may be fun if you realize your never going to have the fastest car on the track, unless your willing too constantly put a good deal of time and cash into the project.
so you build a car too run lets say , a consistent dial-in at 10.00 knowing,
you can go a bit faster but also understanding, you not going to break ,many parts, or push to have the car much faster, You just go for rock solid consistency, nor do much more that trailer the car to the track, and have fun making your competition pull their hair out,
as you've dialed in a consistent 10.00 and your not breaking parts
(you don,t want to go faster as most tracks have much more extensive safety regs for faster cars)
THINK EXCELLENT DURABILITY AND CONSISTENCY, NOT peak power

for an example
lets say my B.I.L. decided he wanted to make his A.C. cobra clone faster
cobra1.jpg

(since you mentioned a cobra clone)
http://www.gtsparkplugs.com/VSECobra.html
http://www.crankshaftcoalition.com/wiki/Talk:General_Motors_transmissions

now If I was starting from scratch I might go with an engine based on either an LS series or a BBC
too keep costs reasonable Id try not to build anything exotic but I would try to gear the car correctly to match the transmission and intended engines power range, and Id damn sure build an engine with solid roller cam valve train and Id get the compression up near 13:1-13.5:1 and build the car based on decent flowing heads, a good single plane, dominator carb, style intake and use of long tube headers with side exhaust pipes.
a DART block would be preferred but you could use a stock 4 bolt block, if the local machine shop checks out the block carefully.
YOU BETTER TAKE THE TIME TO HAVE A LONG & DETAILED TALK WITH YOUR FAVORITE MACHINE SHOP MACHINIST$ about what your trying to do and the cost, AND TIME FRAME!
I like manual transmissions but for bracket racing consistency is important so Id build a damn consistent auto transmission, with a high stall speed torque converter based on what engine I built.
(personally Id go BBC just because I know the engine very well)
don,t forget a decent 7-8 quart baffled oil pan, with a windage tray, and Id certainly use a trans fluid cooler and a large oil cooler,roller rockers and a rocker stud girdle.
you would not need to get very exotic to stuff a high compression .060 over 454 engine, or stroke it to a 489, in a light cobra clone with decent heads and an intake with a solid roller cam too easily crack 600 plus hp
, either, and if you wanted to keep costs semi reasonable Id start looking for good used parts in a block, and dominator style intake manifold, and Id buy a SCAT forged 4340 rotating assembly ,
with 6.385" rods with 7/16" ARP 2000 rod bolts,rated at near 800-1000 hp plus
obviously if your going to spin up a long stroke combo , to higher rpm levels,very high quality components are required.

http://www.scatcrankshafts.com/rotating-assembies/rotating-assembly-product-search/
and try to locate decent flowing performance aluminum, heads.
(trickflow , DART, AFR, PROFILER, or brodix small rectangle port in the 315-320cc range)
I don,t think youll have much trouble getting the car weight down too 2500 lbs-2600 lbs and the engines power to easily exceed, about 540-560 rear wheel hp.
YES I.m well aware that you will not be able to run this on common pump high octane gas and will need serious race octane fuel
talk to your local machinist about any deals he might have access too?
the key here as high compression, decent heads a single plane intake and a solid roller cam with about .710 lift
https://www.summitracing.com/parts/crn-138811/overview/
and gearing the car with something like a 4.11 rear gear and using a 4500 rpm- 5000 stall converter, and getting the suspension set up to give that light car decent traction,so Id set the car up with slicks, and proper suspension mods required.
http://garage.grumpysperformance.co...ngine-displacement-without-disassembly.16217/
blueprint engine blocks
https://www.jegs.com/v/Blueprint-En...brand&storeId=10001&catalogId=10002&langId=-1

DART BLOCKS
http://dartheads.com/product-category/big-block-chevy/blocks/

world products blocks
https://www.billmitchellproducts.com/engine-blocks/

G.M. performance
https://www.gmperformancemotor.com/category/LS196.html


http://www.wallaceracing.com/et-hp-mph.php

related
http://garage.grumpysperformance.co...asonably-fast-in-street-trim.3404/#post-69170

http://garage.grumpysperformance.co...-about-your-potential-dream-bbc-combos.14607/

http://garage.grumpysperformance.co...lding-a-dream-or-wasting-cash.775/#post-30345

http://garage.grumpysperformance.com/index.php?threads/think-thru-your-goals.10606/#post-45536

http://garage.grumpysperformance.com/index.php?threads/very-brief-big-block-chevy-history.951/

http://garage.grumpysperformance.co...a-project-car-have-freinds-similar-cars.5976/

http://garage.grumpysperformance.com/index.php?threads/getting-started-in-the-car-hobby.339/

http://garage.grumpysperformance.com/index.php?threads/matching-parts-and-a-logical-plan.7722/

http://garage.grumpysperformance.com/index.php?threads/another-496bbc.5123/

http://garage.grumpysperformance.com/index.php?threads/big-block-or-ls-series-motor.6866/

http://garage.grumpysperformance.co...54-bbc-engine-have-any-power-potential.12343/

http://garage.grumpysperformance.com/index.php?threads/454-bbc-on-the-cheap-well-to-start.11739/

http://garage.grumpysperformance.co...octane-for-compression-ratio.2718/#post-70006

http://garage.grumpysperformance.com/index.php?threads/octane-boosters.613/#post-12677

http://garage.grumpysperformance.com/index.php?threads/avgas.7751/
 
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maybe someone with a software dyno program,
can use this info and that, info that is currently posted above,
too provide a software dyno chart, for a similar theoretical engine build


heads
https://www.profilerperformance.com/174-bbc-24-degree-heads.html
sniper320bbc.png



cam
crane138811v.png

use 4.25" stroke, 4.280 bore
use open stepped headers,
13.5:1 compression ratio,
and a 1050 cfm dominator carb
and a single plane intake
install the cam retarded 4 degrees
 
Thank you !
I knew that engine combo would work reasonably well as its not much different that the engine I built for my 1968 corvette with the crower stack injection,
(which would further boost power)
its just got updated cylinder heads (better than were available back then) and a single carb
(that will marginally hurt power but cut cost and complexity a great deal)vs the stack injection
and similar compression and cam timing

btw
on most more modern cars theres no easy to access place to hook a tow strap
so if you intend to trailer and race any car it makes a great deal of sense to customize or bolt or weld on substantial loops or rings too the lower frame where a tow strap can be securely clipped in place to tow or secure the car too a trailer

DSC00325.jpg

DSC00326.jpg

DSC00327.jpg

extended tow loops, that extend out past the lower edge of bumper can be added too the forward and rear frame rails on the cars corners, by welding or bolting , to allow secure towing or tie downs on a trailer, these come in dozens of sizes and designs
DSC00328.jpg

DSC00329.jpg

always, if you deal with any machine shop, assume your dealing with a guy who really doesn,t give a crap,
and print out in fine detail , what you want done ,,EXACTLY....with specific dimensions and a diagram,
with ALL those dimensions printed boldly , try hard to get both a firm delivery date and a agreed upon total price
IN WRITING WITH HIS SIGNATURE, and several pictures of the parts and him holding the parts and a receipt
that the parts listed individually, to be worked on are in what ever condition they were in, TAKE LOTS OF PICTURES
this will be a minor P.I.T.A. but it will save you a whole lot of misunderstandings and arguments
never deal with any shop that says things like,
"come back next week I should get too it by then"
or "stuff like that generally costs about$300-$400, but I won,t know until I get into the project"
or won,t give a firm delivery date, price or sign a
receipt, or agree to a firm price... youll see why if you ignore this advice in spades

 
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http://garage.grumpysperformance.co...atios-and-when-to-shift-calcs.555/#post-54233

http://garage.grumpysperformance.co...hing-the-drive-train-to-the-engine-combo.741/

http://garage.grumpysperformance.co...electing-a-torque-converter-stall-speed.1715/

http://www.wallaceracing.com/gear-speed.php

http://vexer.com/automotive-tools/speed-rpm-calculator


Engine01_BBC489_Crane138811a.jpg
BBC489z.JPG


personally a well built 4l80e with a manual shift only option, a 4500 rpm stall converter and 4.11:1 rear gears would seem to be almost ideal here for the intended use, if you stuck that engine in a light car for a weekend toy, you would have an engine easily capable of making the car run consistent 10 second times, and never have to push it near its actual full potential or reve it near its stress limits,
Id bet you could shift it at 6600 rpm-6800 rpm,
and that would put significantly less stress on the engine,
and still run 10 second flat et times
c-clip are the stock or standard O.E.M. axle design, to get the conversion axles sold by several aftermarket suppliers youll want a matched set of
rear bearings and axles
https://www.strangeengineering.net/...kages-components-1/12-bolt-c-clip-eliminator/

https://www.strangeengineering.net/product/gm-pro-race-axles-elim-kit-1-2-stud-kit.html/

https://www.hotrod.com/articles/build-bulletproof-gm-10-bolt-axle-built-c-clip-eliminator/

http://www.moserengineering.com/faqs/

http://chassisengineering.com/index.php?route=product/category&path=4_104

https://www.summitracing.com/search/part-type/c-clip-eliminator-kits/axle-model/gm-8-5-in

https://www.markwilliams.com/c-clip...MI97f1u_Cz3QIVRbXACh2Xfw5yEAMYASAAEgL-SPD_BwE
related threads
http://garage.grumpysperformance.co...ears-differentials-available.1282/#post-36502

http://garage.grumpysperformance.co...ike-i-need-a-hole-in-my-head.4887/#post-13451

http://garage.grumpysperformance.com/index.php?threads/ok-youve-shreaded-your-10-bolt-rear.237/

performance rear differential axle/ differential parts manufacturers & related info

http://www.moserengineering.com/

https://www.strangeengineering.net/

https://www.markwilliams.com/axles....MIjdPBrO2z3QIVi7rACh38PgMhEAMYASAAEgKMsPD_BwE

https://www.currieenterprises.com/

https://www.mittlerbros.com/Automotive-Rear-Ends

https://www.motivegear.com/

https://dutchmanaxles.com/?SID=13e788c48f6972c9ebd5a6a2581b5139

http://www.differentials.com/

http://www.manciniracing.com/drivetrain-parts.html

https://www.hotrod.com/articles/hrdp-1009-bolt-in-rearend-buyers-guide/


http://garage.grumpysperformance.co...-bragged-about-in-this-big-block-chevy.15931/


 
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Rick,
I got asked what the potential result would be if you modified that combo you did too build the similar engine with the mods listed below.
could you please run this software dyno with the listed changes




maybe someone with a software dyno program,
can use this info and that, info that is currently posted above,
too provide a software dyno chart, for a similar theoretical engine build


heads
https://www.profilerperformance.com/174-bbc-24-degree-heads.html
sniper320bbc.png



cam
crane138811v.png

use 3.75" stroke, 4.280 bore
use open stepped headers,
6.535" connecting rods
13.5:1 compression ratio,
and a two 1050 cfm dominator carbs
and a tunnel ram intake
install the cam retarded 4 degrees
 
sure! . THANK YOU RICK!

something similar too this picture I found on the internet, (posted below)on the induction side, of that BBC engine, and the shorter stroke high compression engine with a solid roller cam has some potential to breath better
now I don,t think it would result in quite that peak power the software indicates, theres little doubt that the shorter stroke engine thats allowed to easily breath has potential.... especially if it was correctly geared and placed in a fairly light weight car, like a T-bucket.
you would certainly need top quality forged and balanced components and a manual transmission, or a 4500 rpm stall converter,and shifting at near 7600 rpm, and with nearly 700 ft lbs of peak torque ,a damn good suspension and slicks.
Id be thinking DANA 60 rear differential for sure.

124.jpg

BBC432.JPG

if pockets are deep you have options

ID also point out that torque curve could easily be enhanced with individual runner stack injection

Velocity_stack_detail.png

BBCstacksil.jpg

http://garage.grumpysperformance.co...ifferentials-available.1282/page-2#post-55490
theres certainly advantages to using alcohol ,
significantly cooler engine temps and a bit better power without any doubts.
but one thing I learned using alcohol in any race engine was to be damn sure you remembered,
to run the engine on straight 100% gas,with a dash of MMO,
for a couple minutes before you turn it off and park the car
if you don,t youll have an amazing amount of corrosion related issues in a car thats parked for a week or more between usages

my 1968 corvette with a big block 496, running METHANOL and crower injection, it looked vaguely like this picture,when I tried alcohol for a short time,
mine was Burgundy and a chrome bumper corvette of course
that required a quick disconnect fuel cell, so I could quickly swap fuel tanks,
I had a 15 gallon fuel cell in the corvette, filed with METHANOL, and a quart of MMO, and a jury rigged 5 gallon fuel can, filled with 115 octane gas and a pint of MMO, we carried separately , too the track,
with the proper quick connect connectors to run the car from for a few minutes ,
before we parked it for any length of time to reduce the chances of corrosion.
no mater how fast your corvette, or any muscle car, may be,
if you can,t drive and enjoy it or use it occasionally,
you've lost a good deal of the cars potential and in my opinion value.
thats one reason I've stated several times,
that its generally more fun to run a 11-12 second street car,
you can drive daily, than a 9-10 second car you can,t drive except at the track.
Ive owned two cars that I could rather easily clock low eleven second ,
and for one, high ten second 1/4 mile time slips driving
I miss them a bit more than the low 10 second corvette , I built,
simply because I had far more pleasant memories , WHY, ... simple!
I spent far more time on both the street and track with the more street friendly cars.
both my 1965 tempest and 1969 camaro would run low 11 second times rather easily
my 1968 corvette was extensively modified, full roll cage, modified rear dana 60 differential
injectors sticking through the hood, (and more attention than I wanted)
here,s a picture of me in 1970 (49 years ago) with a 1969 camaro I installed a BBC-496 with a tunnel ram into, then later CROWER FUEL INJECTION
paulscamarobw.jpg

1965gtoside.jpg

I found this picture on line,
its almost a clone too what my GTO/TEMPEST clone, I built with a killer BIG BLOCK CHEVY/MUNCIE 4 speed, dana 60 rear differential, drive train, looked like,
its the one car I REALLY MISS that I wish ID never sold
I had built a 1968 vette, in the mid/late 1970s with a full roll cage, a dana 60 rear and 4.11 rear gears and a m21, and a 13.7:1 cpr 496 bbc engine with crower injectors at the time.
CrowerInjectorsa.jpg

MY 1968 corvette was dark maroon
and a chrome bumper 1968 corvette,
but it looked similar to this corvette with the crower injection sticking through the hood
78CrowerFI1.jpg

I've built SBC,BBC,PONTIAC and DODGE/MOPAR, and even a few FORD engine engines for dozens of cars,
the guys that are happiest are , generally the guys that can jump in the cars they own and drive them on the street without any reliability issues

ID point out that runner air mass & charge inertia stacking up behind the intake valve is at least partly influenced by the length and cross sectional area, in the same way that header primary length & cross sectional has an effect on the DRAW, or negative pressure wave that helps draw in the next intake charge during valve overlap, thats one factor that tends to make the use of tighter LSA, in cams used with stack injection, and use of open headers with a longer effective header collector length, have a wider torque curve in my experience.
its also a factor in why larger diameter cross sectional area , moves the effective torque curve higher in the rpm range and why running a bit richer fuel air ratio tends to run a bit better using stack injection or tunnel ram intakes and to a lesser extent single plane vs dual plane intakes.
that longer and effectively greater mass of intake charge and matching mass of exhaust gasses, have a combined and effectively complimentary effect at higher rpms during that period of valve timing OVERLAP, that greatly adds to cylinder scavenging, as it helps remove spent /burnt exhaust gases, and once the exhaust valve seats the inertia ram effect helps stack a bit more volume of intake charge into the cylinder.
you can feel this and see it in dyno graphs if you compare a stack injection and properly matched header with a tight LSA cam in a high compression engine, vs the basically similar combo with a single plane intake , where you see a marked loss of power in the single plane intake vs the stack injection on what would otherwise be almost identical engine combos, where the shorter and lesser intake charge mass just can't match the cylinder scavenging efficiency, at stacking more intake mass of F/A or scavenging the exhaust as effectively.
I've always rather been amused at the reaction I've seen when I suggest stack injection or a properly tuned tunnel ram intake and a tighter LSA cam, may noticeably boost the engine power band, most guys just don't think there's potentially that much power to be gained, with the swap, and seem shocked and pleasantly surprised with the difference in seat of the pants acceleration/torque they can feel.
I know that the difference when I ran crower stack injection was an instant 3 tenths faster and several extra MPH in the lights
just swapping intakes styles (dominator/single plane vs crower stack injection) on my 13.7:1 COMPRESSION RATIO, 496 BBC
index.php

CROWER no longer sells the exact cam I used but it was very similar to the current
#01486

Chevrolet Mechanical Roller Camshaft - Camshafts

Chevy 396-454 Roller 8620 Steel Billet Camshaft
www.crower.com
www.crower.com


CrowerInjectorsa.jpg


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camcomp.jpg

pistonposition2a.jpg

volumetric.gif


Stoich.gif


volumetricz.jpg




exhaustpressure.jpg




EXFLOWZ4.jpg




fe008d0d1225919353.gif


0607phr_11_z+camshaft_basics+lobe_centerline_angle_determination_chart.jpg


http://garage.grumpysperformance.co...you-regret-selling-the-most.13116/#post-68384

http://garage.grumpysperformance.co...-resulting-from-an-engine-swap.898/#post-1450

http://garage.grumpysperformance.co...best-musclecar-related-memory.2075/#post-5545
http://garage.grumpysperformance.com/index.php?threads/build-a-496-stroker-bbc.101/#post-15067


a few related threads that might help you build a better car

http://garage.grumpysperformance.co...-that-makes-many-of-the-cars-desirable.11244/

http://garage.grumpysperformance.co...-of-grand-sport-corvette-hash-marks-etc.6849/

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