69Laurentian wrote:

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THESE look nice

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and they only cost around $2k

 

my all stock matching numbers big block of 427 cubic feet has .049 heads   poor mans Hot Rod heads

$939 at Jegs

tin indian wrote:

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69Laurentian wrote:

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THESE look nice

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and they only cost around $2k

 

 

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why don't you get  a set of over sized valves I'm guessing your heads are cast iron so you could take them to  a machine shop and get them ported  a little  just so you could get the bigger valves in there lol poor mans performance lol

The cam is a 325 hp grind, Q-Jet and Edelbrock Q396 ( 70's vintage )  aluminum  intake , stock exhaust manifolds ( I don't like headers and am trying to keep the car as original as i can ) 2 1/2 front pipes with rhino mufflers and 2 1/4 tail pipes. The trans is a 5 speed tremac with a 327 first gear and my rear end has 373's  I am not trying to burn up the street I was just wondering if the heads are starving the engine, with the small intake valves and if it could run better by changing the heads. The engine was originally a 396 2 bbl out of a 68 2+2 Pontiac.

Kevin

That cam is hurting the engine most of all... its too small. On a budget, even a summit 1301 would be a noticeable improvement... the heads aren't the weakest link in that combo, yet, imo. If you get the exhaust to breathe and step up to a larger cam, then perhaps upgrading your heads would add benefit...

do you know what your timing is set at? at idle and all-in? having a properly set up distributor was a HUGE change in my 396....seriously worth it. I have a very similar set up to yours, stock heads, summit 1300 cam, headers, etc. I wish i had a bigger cam in it, it runs way too smooth for my tastes... but it has enough power to push you back into the seat a bit...

I think if you change the cam, and bump up the timing, you'll have a smile on your face!!

ak

ps with those gears you are probably running out of cam so quick as well...it falls flat at around 4700rpm, more cam and you will also be able take advantage of a power band for a bit longer (lets say 5400rpm). Just make sure you replace the springs too!

-- Edited by ak 67sd on Thursday 17th of February 2011 12:52:15 AM

I have some 781's for sale cheep but i'm afraid the shipping from here would ruin the good price.  I have 781's on my big block. Had them cut for 2.19/1.88 valves and a nice porting job done.  Altogether cost about $700 (including new stainless swirl polished valves and springs to match my new cam.) Very happy with them.

I went with stock heads 3degree valve grind 7/16 push rods high volume oil pump cam was 550/525 280/290 crane cam with double roller timing chain. Torker 2 intake with 780 holley and HEI ignition. A turbo 400 with stage 2 shift kit and 2500 stall helps it idle at a stop sign. At the rear is stock 10 bolt posi with 3:08 gears. It is nice to drive,sounds good and not bad on gas.O i forgot headers 3 inch to turbo mufflers 2 1/2 to tail pipes.

69SD wrote:

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I forgot that I did change the cam to a Crane  CHQ 272 H10 last year and drilled out my primary jets from .071 to .073, everyone I talked to says that those heads are a open chamber and were the lowest hp rating from gm 265 hp!  also went to a crane breakerless ignition and a higher output coil. So this is why I am inquiring !

KC

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 Yup those heads are open chamber and used on some of the lowest output big blocks. Their also some of the best flowing bbc heads gm made. I've seen lots of builds well into the 700-800 hp range with these heads.(thats with port work and bigger valves.)

 

Those motors were low hp because of low compression, restrictive intake and exaust. It doesnt take much to wake those motors up.