Head and Cam Swap, 82 CFI

Drawmain · Jun 1, 2014

I'm looking to freshen up the CFI in my 82 Vette and I'm parts shopping. I'm looking to replace the cam and heads at the least, depending on what I find internally once the heads are off I may end up with a full rebuild. The parts I'm looking at are as follows:

Heads: Dart SHP part number 127221 ( Summit lists it as DRT-127221)
Cam: Lunati Voodoo 10120701
I'm most likely going with Comp Cams Magnum 1.52 ratio roller tip rockers. Push rods will be chosen after length needed is checked and verified. I'm looking at using a FelPro 1094 gasket.

I've never used aluminum heads before. The car will not be raced, and the original CFI ECU will be used. One other possible upgrade will be a Renegade intake manifold when they become available. My current manifold has been ported to open up the runners and remove the EGR channel. Any advice and wisdom will be greatly appreciated, as well as any part suggestions. This car may end up being a daily driver once I get it all worked out so I'm looking for reliability and excellent street manners over top end power. I live under 5000 rpm and I prefer low and mid range torque. Am I on the right track?

philly · Jun 1, 2014

although you are on the right track, i think a carb conversion will do alot for you as far as ease of use, torque production,and depending on the parts you choose, even fuel economy.

the stock intake flows something like 170 cfm and even ported its a serious restriction to engine efficiency.

heres some cross fire related reading material.

viewtopic.php?f=38&t=10240&p=40947&hilit=cross+fire#p40947

viewtopic.php?f=32&t=102&p=143&hilit=1984+crossfire#p126

viewtopic.php?f=32&t=640

viewtopic.php?f=32&t=303&p=986&hilit=1984+crossfire#p368

carb swap specific:

viewtopic.php?f=38&t=1914&p=39878&hilit=cross+fire#p39878

as always on grumpys performance reading the links and sublinks will literally enlarge your mind. my head barely fits through doorways anymore because of how swollen it is with knowledge.

Drawmain · Jun 1, 2014

I read through all the links, thanks for posting them. Some of them I'd already read through prior to today. I do agree a carb swap would be easier, but I would like to stick with the CFI setup. As stated I'm not looking to race or anything, so I can live with the restrictive intake for a bit until the Renegade becomes available again. It may become available before I'm even done with the head and cam swap, so I know the stock intake days are numbered. I really would love to find an old Offy CrossRam to play with. I found a couple on eBay, but they are priced higher than the Renegade so I'm waiting for the Renegades to be available again.

grumpyvette · Jun 2, 2014

if it was my engine theres zero question in my mind that I WOULD VASTLY PREFER THE similar dart 200CC PORT HEADS WITH THE BETTER VALVE SPRINGS increased .620 lift clearance potential, that will be useful ,especially if you ever decide to upgrade,while the 180cc heads more or less lock you into the low and mid rpm power band, the difference is minor but its silly in my opinion to spend money twice when a bit of thought on the initial purchase will prevent wasted money later and the difference in the lower rpm power curve will be un-noticeable, because even with the larger port heads its still going to easily exceed the stock power curve, and an increase over what your used too. the approximate 10% increase in port volume is the result of approximately a 5% increase in port cross sectional area which has a minor effect on low speed torque offset but a similar increase in upper rpm power potential, and while you might not think thats a great trade as your looking for lower rpm torque the difference in the power curve is still in your favor even if you don,t regularly exceed 5500rpm , a software dyno prediction ill post below may not give exact numbers youll see but it will surely predict the trend, and be useful
http://www.summitracing.com/parts/drt-127422/overview/

WATCH VIDEO
https://www.youtube.com/watch?annotatio ... v3ZkqZiMjI
the cam will be fine in this application
Lunati Voodoo 10120701

I would certainly step up to 1.6:1 ratio roller rockers and verify clearances as they could potentially add 15-20 ft lbs of torque
http://www.summitracing.com/parts/csp-s1002

between the better flowing heads, more efficient cam and low friction rockers, once you find and install a renegade intake and add decent headers,the combo could easily boost power levels well over 60-70 plus hp, but youll feel the difference over the whole power curve, because the stock heads, cam and intake are highly restrictive

http://www.ehow.com/list_7628885_1984-c ... specs.html

The STOCK L83 engine makes 205 horsepower at 4,300 rpm and 290 foot-pounds of torque at 2,800 rpm
'
heres what DD2000 soft ware predicts that 200cc dart head, renegade intake /lunati cam with 1.6:1 roller rocker and header combo produced at the flywheel, so any concern over large port heads killing low rpm torque should be dismissed as the vastly better flow easily compensates, now the roughly 350hp and 400 ft lbs of torque may not sound impressive until you realize thats probably 100 more hp and 50 more ft lbs at the rear wheels than the stock engine produces

Drawmain · Jun 2, 2014

Grumpy, thanks for weighing in on this. I looked at the 200 cc head but I was concerned that I would loose low end torque if I went above 180 cc. Since the heads are priced the same I'll update my list to include the better heads. Are there any issues I need to be aware of with aluminum heads? I've never installed a set before, so any information you have is welcomed.

grumpyvette · Jun 2, 2014

youll need to use the correct matching head gaskets of course, and Id strongly suggest ARP head bolts with washers as stock head bolts tend to be both the wrong length and give the wrong clamp load reading with a torque wrench, youll want head gaskets as close to .018-.022 thick as you can find that are designed for those aluminum heads (check with the cylinder head manufacturer on both the suggested head gaskets and head bolt part numbers)

btw the 12 point head bolts ID use are ARP part # 1343701
keep in mind the head gasket bore must be larger than the block bore diameter and in spite of printed directions suggestion installing the gaskets dry in most cases , I install all had gaskets sprayed with a good damp coat of copper coat on both surfaces and torqued in place while damp/tacky, after first carefully cleaning with acetone and drying surfaces on heads and block.

viewtopic.php?f=52&t=4478&p=19555&hilit=thread+sealant#p19555

http://garage.grumpysperformance.com/index.php?threads/refresh-1982-crossfire-vette.14173/

viewtopic.php?f=52&t=1376

viewtopic.php?f=52&t=697

viewtopic.php?f=44&t=799&p=1161&hilit=erson+break+in#p1161

viewtopic.php?f=52&t=1489&p=3360&hilit=erson+break+in#p3360

BTW I found this site listed as selling renegade intakes???

http://www.eddiemotorsports.com/product ... -cart=6314

Drawmain · Jun 2, 2014

I am aware of Eddie MotorSports and I am on their mailing list once the Renegade intake becomes available. I missed the last run, but I'll get the next one. Apparently they sell out rapidly, I don't know if that is due to low production numbers or what. Apparently there are a lot of CFI owners out there clamoring for these intakes!

The Dart website recommends the Fel Pro 1003 head gasket for the SHP heads, but the compressed thickness on that gasket is .040, which will put me outside of the recommended quench you stated. The Fel Pro 1094 has a compressed thickness of .015 which keeps me in the quench, but the bore is 4.100 compared to the bore of the the 1003 at 4.166. Which would you recommend for my application? I'd like to avoid decking the block to preserve the numbers on the block if at all possible.

grumpyvette · Jun 2, 2014

.015 thick on the head gaskets getting very close to critical and while its probably going to work Id be very hesitant to go below .018 as a minimum and feel far better at .020-.022, as far as the 4.100-4.160 thats not nearly as critical as long as the gasket bore of the gasket exceeds the block bore and is concentric youll be fine.

SCE seems to make what you need
http://www.jegs.com/i/SCE+Gaskets/829/511152/10002/-1

viewtopic.php?f=52&t=4403&p=38976&hilit=head+gasket+bore#p38976

87vette81big · Jun 2, 2014

There has been supply problems with those Renegade intakes since 2007-2008.
I myself steer clear of them alltogether.

Drawmain · Jun 2, 2014

Unfortunately unless you can find a good Offenhauser on ebay, the Renegade is the only cross ram in town, I will not backorder it, I will only order if they are in stock and shipping. I've seen two Offy's on eBay thus far, but both were priced higher than the Renegade. I have time, so I'll wait.

Drawmain · Jun 15, 2014

Since the cam I've chosen is Hydraulic Flat Tappet, I'm wanting to insure that the springs that come with the Dart heads will be okay without undue risk of wiping cam lobes. Lunati's recommended spring with the cam I chose has an open pressure of 98 @ 1.75 installed height and an open pressure of 330 at 1.25 (.500 lift) with a 462 lb/in rate. The Dart springs on the head listed above are 130 @ 1.80 installed height and an open pressure of 375 at 1.20 (.600 lift) with a 409 lb/in rate. Will I run into problems during break in of the cam with those springs? What about during normal operation after breaking in the cam? Using the 409 lb/in rate, the Dart springs would be at approx. 334 @ 1.3 so that makes me feel a little better, but I wanted to ask to be sure. I don't want to wipe a cam lobe. Using 1.6 rockers my max lift on the exhaust valve would be right at .500 and the intake is around .484.

grumpyvette · Jun 15, 2014

stock valve springs or even upgraded valve springs in that load rate range are usually available dirt cheap and very easily changed, so , if you are not going to need the stiffer valve springs ,ID simply swap the springs, put the stiffer springs that came on the dart heads in a correctly labeled card board box, spray them down with a good coat of marvel mystery oil and slide that box in a double sealed zip loc bag for future use

example 30 seconds looking
http://www.ebay.com/itm/SBC-Small-Block ... 98&vxp=mtr

For sale - new set of 16 Z28 style valve springs for small block Chevy V8 engines. These springs are stock diameter 1.26". Ideal for cams in the .480"-.520" lift range with a max of .550". Seat pressure is 110lbs @ 1.750", open pressure 325lbs @ 1.200". Coil bind at 1.15". Free height of 2.035". For the money you can not beat them!

KMJ PERFORMANCE

- TECH AND EBAY PAYMENT LINE -

515-733-2890

Drawmain · Jun 15, 2014

Good find! I went back and looked at the Lunati website. They also had an upgraded recommendation for the same cam, so I looked up the numbers on those. Lunati part number was 74818-16 and the specs were installed height 1.8, seat load 130, open load 313 @ 1.2, almost identical to the springs that come on the heads, so I think I'll just quit worrying and go with the springs that come with the heads.

Cam Spec Card: http://www.lunatipower.com/CamSpecCard. ... mber=60101

Baseline springs: http://www.lunatipower.com/Product.aspx?id=6711

Upgrade springs: http://www.lunatipower.com/Product.aspx?id=472

Indycars · Jun 15, 2014

Correct me if I'm wrong please, but this looks like where the flat tappet camshaft
has the advantage over the roller. I like to calculate the Hydraulic Intensity for
camshafts when I'm looking at its parameters.

My understanding is the flat tappet cam, can physically lift the tappet faster
initially than a roller cam. It's like the sprinter and the long distance runner,
the flat tappet is the sprinter and the roller is the long distance runner. For
short lifts(shorter distance) the sprinter will win the race.

HI = Duration (Seat to Seat) - Duration (@ 0.050")
HI = 256 - 213 = 43 [Intake]
HI = 262 - 219 = 43 [Exhaust]

87vette81big · Jun 15, 2014

David Vizzard touched on the subject years ago Rick.
He Felt a Solid Flat Lifter could achieve higher intial Ramp Speeds on open Intake & Exhaust events compared to a Race Roller solid cam.
But he stated the Metalerolgy wasn't in place to prevent cam lobe wiping.
Its still a Big problem in full race engines with roller solid cams.
Lifter wheel trunion bearing fails & takes out the mating cam lobe.
I think its the Tremendous lifts guys are using today.
.750-1.00". Lots of open spring pressure required.
Very high seat pressures of 400# or more.

Told for years to never use more than .480"-.510" lifts if you want 50k mile longevity.

Olds cheated by using 39 degree lifter bank angles after 1966.
Drawback was valve geometry not so ideal.
1965-66 had 45 degree lifter bank angles like Chevy & Pontiac.
Starfire & Torandos had special .924" diameter lifters unlike other usef .841" by Olds, Pontiac & Chevy.

87vette81big · Jun 15, 2014

Fords & Mopar V8's have large diameter lifters too.
Raises Ramp speed automatically .
Gives them an edge most dont realize exist.
Why a Renegade 5.0 does miracles with seemingly norhing special.

Indycars · Jun 15, 2014

Yes David Vizard's book is where I read it.

It's a physical/mathematical limit for the roller initially. The larger the flat lifter
diameter, the better the lifter acceleration in the beginning.

87vette81big · Jun 15, 2014

David is kinda a Pontiac guy in Chevy Clothing.
He likes Averages.
Likes Low Lift & Midrange Flows..He sometimes uses a 30 Degree Intake Seat on Chevy Race Heads
All Azz backwards to most observers.
He has been at along time though.

87vette81big · Jun 15, 2014

Camshaft Lobes & Lifter contact faces & Roller lifter trunion wheel durabilty is increased too Rick with a Larger diameter lifter.

grumpyvette · Jun 15, 2014

within certain limits ,the larger the lifter diameter the faster the cam lobe acceleration ramp can be, chevy has a lifter diam. .842
ford uses a .874 diam, Chrysler .904 diam.

but if your willing to pay for special cams and insert solid flat tappet lifters from the cam tunnel side you can use mushroom base race lifters in a chevy, and surprisingly , part of the limitations in use was the spacing of the adjacent cam lobes,and lifter base interference with each lifter spinning freely in its lifter bore

Head and Cam Swap, 82 CFI

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