What is a good cylinder head to use on my .030 over 396 ? The engine came out of a 1968 Pontiac 2+2 ( 396 2 bbl ) so I think the heads might be wrong with my cam and Q-jet. I checked out the casting numbers and its 3933148, I would like a little more punch from my rat and wondering if heads with a bit bigger valve would help out ? I am not try to set a record for the quarter mile so I would like a cast head so I can have some driveability.
The 781's and the 049 casting numbers (last 3 digits) are the best oval port heads that GM made for performance. Nothing wrong with them at all up to around 550-600hp with the larger 2.19-1.88 valves installed and a lil' bowl hoggin' and gakset matching. Lots of people run 'em including me on my 496.
The 781's and the 049 casting numbers (last 3 digits) are the best oval port heads that GM made for performance. Nothing wrong with them at all up to around 550-600hp with the larger 2.19-1.88 valves installed and a lil' bowl hoggin' and gakset matching. Lots of people run 'em including me on my 496.
YUP. If you have to buy a used set and get them done, you should be able to get away with $400-$700 total investment.
Ah, that'll be a standard re-build with a 3 angle valve job, not what Carl has above. ( In my neck of the woods)
-- Edited by 68post on Tuesday 15th of February 2011 10:40:23 PM
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
You have good heads on there (depending on how much hp you are looking at making!)... the weakest link in that engine (and other low hp 396s) is the cam... and of course timing if you're dialed in at stock specs...it kills the engine! What cam do you have? intake?
Without knowing more about your combo, first steps are lunati 60202 (or 03) cam, 4bbl, timing in the range of 24 base and 36 all-in (factory is retarded!)
...if you want more, put larger valves in the heads 2.19 intake, and go with the bigger of the 2 cams... 2400 stall, what gears do you have? 1.75" headers...
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.
with that much trans. multipication 3.27 x 3.73 and a big block, and stock manifolds you REALLY don't need more heads (2 cents)
put the headers on and then you need heads
My engine has a cam sooo big, it was put in in two pieces, to clear the lobes and then had Rhodes lifters added to bleed it down, with a race prepped carb and the super charger and 250 shot NOS it makes 1400 horse power at 7200
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
My engine has a cam sooo big, it was put in in two pieces, to clear the lobes and then had Rhodes lifters added to bleed it down, with a race prepped carb and the super charger and 250 shot NOS it makes 1400 horse power at 7200
Are you telling tall tales again?
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Prince Edward Island
'64 Parisienne CS "barn find" - last on the road in '86 ... Owner Protection Plan booklet, original paint, original near-mint aqua interior, original aqua GM floor mats, original 283, factory posi, and original rust.
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 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 !
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.
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
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.
nothing wrong with your heads, definetly a rebuild with bigger valves and bowl work, and the guys are right stock 325 horse cams have very small lobes, something with a .500 or so lift and under 290 duration with dual pattern more scavenjing on the exhaust would wake it up and keep it driveable
