Too much head for street motor???

-

challenger57

cuda57
Joined
Sep 21, 2007
Messages
207
Reaction score
26
Location
york, pa.
Can you have too much head for a strictly street HP motor. Here is my motor build-400 stroked to a 471, 586 solid roller cam with 114 degree LSA to support a Dual quad fast efi system, tremec 5spd 4.30 gears all rolled up in a 63 valiant. I am considering a set of 440 source cnc heads which they say flow 320 cfm. Since this car will probably not see any track time, will all that flow possibly hurt my bottom end while doing more cruising time than top end time. Would I be better off just getting a set of non ported stealth heads and just gasket match the intake and heads for better bottom end. I forgot to mention the compression will be right around 11:1. This is a fully tubbed and caged car. I will probably have to change my gears a bit since my rear tires are only 29" tall. Thanks All
 
Well I believe they would fit just fine. Just "street cruising" you most likely wont use the top end power but it will be there when you need it.
 
Sounds good to me but wut up wif da 114 LSA? Is that something the EFI people recommended? That sounds kinds like wussin out unless it's sumffin specific they are recommending....and if it is, I'd ask them why.
 
with 471 cubic inches you wont hav to worry about bottom end power or torque just my opp.
 
It depends on the new volume of the heads' ports, and the mid lift flow. Most porting is a compromise between high and low lift flow. Your cam is relatively small (street engine) so the valve will ony see about .560 and for a very short time. What are the flow figures for .200, .300, and .400?
 
Id just dump that cam and get something in the 630 lift range. If you are going to all the expense of a roller you really have nothing to lose going to something that will thump.
 
Can you have too much head for a strictly street HP motor. Here is my motor build-400 stroked to a 471, 586 solid roller cam with 114 degree LSA to support a Dual quad fast efi system, tremec 5spd 4.30 gears all rolled up in a 63 valiant. I am considering a set of 440 source cnc heads which they say flow 320 cfm. Since this car will probably not see any track time, will all that flow possibly hurt my bottom end while doing more cruising time than top end time. Would I be better off just getting a set of non ported stealth heads and just gasket match the intake and heads for better bottom end. I forgot to mention the compression will be right around 11:1. This is a fully tubbed and caged car. I will probably have to change my gears a bit since my rear tires are only 29" tall. Thanks All

You won't need the cnc deal. Mild porting would be more of a benefiet and would keep port speed up so TQ would be good plus the wide lca cam will love low lift flow. 11:1 is a little high for true pump gas IMO.
Brian
 
Just put the heads on and go for it. One thing I learned about the internet is that everyone loves to bench race on topics like this. The fact of the matter is you won't know until they are on there if you like it or not. Don't get me wrong there is a ton of good info and experience to be had on here but nothing replaces your own experience with the set up.good luck.....i look forward to the results.
 
Do it! Better to have too much than not enough. Kinda like "no replacement for displacement"
 
I don't know if every one dipped into the egg nog too early, but by your description, your motor is far from a 'street' engine. I think it would be an absolute dog until your in the 4k rpm range. my 2c
 
I don't know if every one dipped into the egg nog too early, but by your description, your motor is far from a 'street' engine. I think it would be an absolute dog until your in the 4k rpm range. my 2c

Why B/C of the heads or Cam?
 
I agree with Uscg charger on the bench racing thing! So here are some facts on the stealth heads...intake port is 268 cfm unported, 286 cfm with a litlle clean up pocket port and gasket match, CNC ported is 313 cfm. These tests ere all done on the same bench using same heads. The cnc porting was duplicated off of 440 source supplied CNC ported heads to make the test valid. Also when we flowed all 3 versions of this head 1 thing stayed constant...The flow had a great climb to .600 and then it just table topped/ flat lines from .600 and up! also be sure to RE-TORQUE the head bolts on these heads...The aluminum is softer than the more expensive heads and will sqeeze down and loose troque on the bolts! choose your cam accordingly!! Your cam with the wide lsa will have a smoother idle and bleed a little of the comperession but with your stroker you will have pretty stout combo when you hit the street. Are you going to dyno the engine? and remember if there was a PERFECT recipe for an engine we would all have the exact same combo...I used to listen to alot opinions when I first started building my wrecks and I spent alot of time and MONEY changing things with little results! Now I do my own reseach and spend my money testing the stuff I buy...I have my heads flowed and buy my cam according to the flow and with an lsa set for Idle quality needed and compression. Then dyno the motor wich determines what size converter and gears I will need. I put this last wreck together cheaply with good matched parts and I have pounding on it for 4 years
 
-
Back
Top