535 talldeck 427 build help needed

8

81cr450

New Member
This is what I have so far

Dart 310 pro1's 121cc chambers
4.350 bore talldeck 427 block clearanced like a 383 sbc block filled to the bottom of the water pump holes
Eagle 4.500 4340 forged crank
Eagle 6.660 rods w/ arp 2000 bolts
Mahle 4.350 bbc power pack pistons , FSR type forging 10.5:1 18cc dome
ATI dampner
Holley Pro Dominator tunnel ram
80 Camaro call it 3200 lbs after diet if not lighter, gearing is 373 but not comitted to it at all, 4l80e trans

This is a REALLY slow build I've been at this a piece at a time for awhile now but I could use some carb and cam input as they're next up on the list to buy. I work in a shop assembling motors but we dont do HP BBC & I dont have the cash for trial & error so I'm hoping Grumpyvette can help me with some of his dual quad wisdom. Everytime i search dual quad youre posts come up all over the net

The cam I'm looking at is a lunati single pattern with these specs. duration 249 @ .050 IN & EX, 279 advertised, .663 in & ex lift with a 106 lsa , solid roller

Purely a toy that i wanna drive like its a 2stroke 4 wheeler if that make sense

Not set on cam or carbs this is just my first BBC build & I want something stellar that works, I'd even consider odd carbs like side draft dellorto's or even mikuni's or keihin's off motorcycles, linkage would be a pain but I do work in a machine shop with plenty of tools & a little skill

Thanks for your time & I hope this is in the right section
 
that cam in that displacement with that stroke is going to make one nice torque monster combo,but its going to be running close to detonation,due to the intake close time, at a minimum Id install that cam 4 degrees retarded,or strait up, even if correctly set up, but remember that engines not going to be spinning over 6000rpm if you intend to keep it in one piece as piston speeds will become rather high.
I don,t see that tunnel ram intake thats got very large runners designed for very high rpms as being ideal for your application, yes theres no doubt you can get it to work, but Id select a cam with a bit wider LSA and a bit more duration, if this is basically a weekend toy and you want to run pump high test gas, and given the fact youll rarely be spinning a 4.5" stroke big block much past 6000 rpm if that a hydraulic roller might make more sense here.
why not call at least 4 cam company's and get their suggestions, as to a good hydraulic roller cam matching your needs.
now you can run a tunnel ram and get it to work but in this case Id be thinking a single plane intake with a large dominator style carb a better choice for the application

http://www.profilerperformance.com/bbc- ... e-206.html

chevellerestoration480.jpg


now you do have options, we can get into selecting a different tunnel ram intake or using the one you have and dual quads but please think that info over a bit


this ERSONS well known for working well with a manual trans and at least 10.5:1 compression , and a 3000rpm stall converter and 3.73:1 rear gears , used in several engines
http://usaperform.com/performance-lifte ... rers_id=27
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Awesome thanks for taking the time to respond, looks like I have alot more research to do.

I won the intake on ebay for $200 new with spacers & just got an email saying it was stollen out his storage unit so he refunded. I wonder if it really got stolen or if it didnt sell for as much as he thought it should have. Oh well it wasnt right anyway, saves reselling it.

& as much as I hate sitting on hold, your right on calling a few cam tech lines to get the right cam rather than some internet forum recomendations

Thanks for all the links, now for some heavy reading.

BTW I love the shot of the 350 bottom end blow to smitherines, I've seen it on a 302 ford & a couple poorly tuned duramax's but thats the first 350.
 
its not all that hard to calculate ,approximately the most efficient cam lift, duration, and LSA of a cam in an engine, if you know the cars tire diam. car weight, drive train gear ratios, engine compression displacement, head flow numbers,port cross sectional area, valve size, and a dozen other factors, its just that very few people that even understand what they need to look at and how each factor effects the combo,take the time and effort to do so , even the cam company Techs rarely bother, to factor in all the related components, but if you were to call lets say 7 cam companies and lets just as an example say that these were the suggested cams,
you can start with this
FREE software
http://www.camquest.com/
and the linked chart info, use both as a base line, but remember to call at least 5 cam companys and 7-9 would be even better as it virtually eliminates the chances of some moron giving you bad info, that will screw up your cam selection


READ THESE LINK s
viewtopic.php?f=52&t=82

viewtopic.php?f=52&t=1070

USE THIS SOFTWARE TOOL
http://www.compcams.com/Camquest/default.asp

lets just say you got THESE HYPOTHETICAL EXAMPLES as suggested cams

(1) 245 /245 dur 106 lsa .600/.600
(2) 255/260 dur 108 LSA..630/.645
(3)252/258 dur 110 lsa .600/.630
(4) 260/267 dur 112 lsa .650/.650
(5) 246/249 dur 112 lsa .595/.610
(6)250./250 dur 110 lsa. .580/.590
(7) 260/270 dur 106 lsa .670/.690

your average would be
253/257 dur 109 .618/.630 , so you could reasonably assume that you would be very close to correct if you selected a cam with close to those specs, (cam # 3 IN THIS CASE COMES CLOSE) but look at the range, suggested 245 all the way to 260 , intake duration and 106-112 LSA , thats fully 15 degrees spread in intake duration and 6 degrees in LSA, is it any wonder that most guys have a problem selecting cams when theres that much latitude in even what the cam tech guys suggest, let alone the guys on the internet who may be far less knowledgeable and just suggesting what they read worked in some magazine article on an engine that was only slightly similar designed for a car and drive train that bore little resemblance to your current application, thats why I always suggest getting a few cam company tech guys input, and by averaging the results you can effectively find and easily see , the OFF THE WALL SUGGESTIONS, and YES , RARELY SOME TECH SUPPORT GUYS SEEM TO BE CLUELESS MORONS
IVE had best results sticking with CRANE,CROWER, and ERSON generally
given a choice between two similar cams for a street car, selecting the lower duration, wider LSA and LOWER lift generally produces a better more durable combo for a daily driver car engine, or put a different way trading increased durability and lower stress over a bit more peak horsepower is rarely a bad idea if your dependent on the car for transportation

If you read thru the links youll eventually see WHY and HOW a cam is selected and WHY the duration, lift and LSA are important
 
I've read most of saturday & sunday & a little tonight, half blind & my brain has that lovely pudding feeling. So far this is what I figured out from the info you answered me with, yes I do feel a little dumb for not having just searched it.
Anyway with a piston speed of 4860 at 6500rpm a solid roller isnt necessary where a quallity hydraulic setup will get as high as this can spin period. My heads are a little big, by darts "360 cfm" sales quote. I do have a sf600 at work & could jb weld the port floor to get it down to the optimal 330cfm that the motor/rpm will require. Probably just match the good ports to the poor ones. I dont know if that would be a must but it could help some, I assume. The lobe centerline angle says 100 lca , but it is off the chart with a figure of 29. 535 ci with 2.3 valves. I do have more reading on what to do to answer my questions, but I did want to say thanks again & let you know I am trying to use the info.

Still interested in the tunnel ram but if I read the chart right I'd need a 14" runner length manifold & that just doesnt sound feasible. Cheaper cost & simplicity generally are the better coice , I just like to complicate things.

ALOT of great info
 
I would suggest a cam with a LSA no tighter than 104-108 , while its true the tighter LSA would allow the engine to breath better a wider LSA will spread out the torque peak, and a bit of compromise is usually best here, Id also limit piston speeds to about 4300fpm, simply because it will tend to build a more durable combo.
keep in mind the cam timing, fuel octane and compression ratio must be an approximate match to prevent detonation
 
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