402 heads

New to the forum and out of hotrod circulation for 15 years. I changed hobbies 15 years ago and now decided to get back in to it. I bought a 70 chevy 1/2 ton with a small block. I sold the sb and just picked up a 402 for it. Herei s my plan and question. I am going to go 30 over with 9.5 to 1. I will be using a .560/.572 lift cam, I will use stainless valves 2.06/1.72, roller tip rockers,performer rpm intake and 750 carb. All this infront of a 700r4 and 3.73 rearend. I want to know if I should use the stock heads and should I still use the exhaust valve rotators under the springs, or should I spend the money for better heads aluminum or cast. It will be a daily driver.

Thanks, Wes

heads can be made to work and you should use a exhaust rotator elimintors any machine shop that builds bbc should help with this . on the cam... lift tell me nothing about the cam so less you have the @050 .and lsa. roller tips rockers are a waste of good money go roller rocker or long slot steel stamp

It has 218/228 int/exh at .050
I would like to be in the 9.5 cr with the 119.8 open chamber heads , any piston recomendatips?

look at the KB icons there forged line pistons are one that make a piston for the 119 chamber heads . just built one for sale 10.3cr with a hyd roller 220/226 lsa108 547/557

Pat, Do you think full roller rockers will fit under stock valve covers. Can you use reguler lock nuts on the rollers or do you have to use the poly locks?

Wes

i have done it many time s the cheap copy covers chrome the baffles may hit use the 5/16 cover gasket or stack a set of gaskets . the comp steel body . crowers. and crane cast and gold body rockers i have had them clear with poly locks

Wes-I think it is important you note Pat speaking about a hyro roller.

I have been able to double up the older cork gaskets by using an appropriate adhesive and this has given me enough clearance on my 468" Gen IV in my 69 Impala. This works with the older style valve covers that have a flat surface where they attach to the heads. The stock type Gen V and VI covers that come with those engines have a rubber string-like gasket that won't work unless you machine the covers to permit use of the old style.
I also have seen the roller rocker poly locks machined to permit clearance but that may be a little bit of an expense that may not be worth the trouble.
Good Luck

I took my block and heads to the machine shop today. I am not sure the stock exhaust seats will clean up. It looks lie water my have set in the ports and rusted them. If the heads are not cracked I guess I would need to put in new hard exhaust seats. If I have them do that, should I go with the 1.88 valve? Should I have them cut in the2.19 intake valves? Any real gain in doing that? I did find speed pro has the pistions I need. Just to recheck I canI run a closed chamber piston (L2328NF) In an open chamber head. The piston has a .319 dome and I have 119.8 c.c. hambers.

Wes

you may see a gain in the bigger intake i built many bbc 396 both with bigger valve s as far as rust on seats you can cut the heads for bigger valves just to clean up the rust or like you said cut the head for a seat for the stock valve or but a bigger seat for the bigger EX this is your call as the builder. when i get this far in a bbc head most times i go to a 11/32 stem stain less steel valve helps abit on flow . there is many ways to go on the heads.pistons but i would look at the KB icons pistons. need to check the dome shape it can hit on some heads do you have the casting number of your heads ? i can under stand wanting to build something your self or having a machine shop that you trust start a build for you and watch grow to finsh. But i have a very nice 396 .030 =402 fully hyd roller engine that would save you $$. using a flat lifter cam is something i do not do much any more on the older bbc .i still do some solid flat lifter cams in bbc with hi lube lifters . i started using Roller cams in most all my BBC builds over 15 years ago just not worth the price of ripping it apart if break in fails to save a buck on a flat lifter cam some guys will say it,s not worth the added cost and some of them guys are happy building a engine as good to what Gm built it. they may not want to spend the time or money or do not have the tools and machines or knowledge to build them better then GM .. thats what i do every day . if needed i can help you build what ever you would need in a bbc have many as this is what i do every day at my machine shop been building bbc for over 25 years ,this is some of the BBC engines. there is many 454s in there and a 632 big chief . 568. 402. that just went out my shop doors all machine work done in my shop .

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Originally Posted by pat mccarthy

you may see a gain in the bigger intake i built many bbc 396 both with bigger valve s as far as rust on seats you can cut the heads for bigger valves just to clean up the rust or like you said cut the head for a seat for the stock valve or but a bigger seat for the bigger EX this is your call as the builder. when i get this far in a bbc head most times i go to a 11/32 stem stain less steel valve helps abit on flow . there is many ways to go on the heads.pistons but i would look at the KB icons pistons. need to check the dome shape it can hit on some heads do you have the casting number of your heads ? i can under stand wanting to build something your self or having a machine shop that you trust start a build for you and watch grow to finsh. But i have a very nice 396 .030 =402 fully hyd roller engine that would save you $$. using a flat lifter cam is something i do not do much any more on the older bbc .i still do some solid flat lifter cams in bbc with hi lube lifters . i started using Roller cams in most all my BBC builds over 15 years ago just not worth the price of ripping it apart if break in fails to save a buck on a flat lifter cam some guys will say it,s not worth the added cost and some of them guys are happy building a engine as good to what Gm built it. they may not want to spend the time or money or do not have the tools and machines or knowledge to build them better then GM .. thats what i do every day . if needed i can help you build what ever you would need in a bbc have many as this is what i do every day at my machine shop been building bbc for over 25 years ,this is some of the BBC engines. there is many 454s in there and a 632 big chief . 568. 402. that just went out my shop doors all machine work done in my shop .

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Pat those are so sweet looking bud.Very nice!!.

The casting number on my heads is 6272292. I looked at the kb icons but I only see a .180 dome and would only give about 8.3 to 1. I would really like 9.5 to 9.8 to 1 whick I can get with the speed pro L2328nf. They have a .319 dome. Do you think just grinding bigger seats will last long term vs the hardened seats. Which is your prefered roller rocker you use?

Thanks for all your advice, Wes

Pat McCarthy, is that a 302 SBF in that line-up? Roller Cam motor?

no them heads are not 119 from gm less then that . last set i did was 113 cc with the icon zero head ROL head gasket 9.5 cc head gasket .the CR ended up at 9to4 Icon make two pistons 1c9948 and ic9949 10.6 at a 119 chamber the ic9948 are the ones i used with the 292 casting you can get to 9.3 to 9.5 i do not grind many seats any more a cut them with my tobin arp with the 3-D Hp or mondello cutters. that head is some what hard as gm inducted the EX side .for selling point i put seats most all the time . i done many with out hard seats if not beat in they seem to hold out well. roller rockers i use has alot to do with spring Lbs but the scorpion /howards /pbm rocker .or harland sharp .new comp Ultra Pros . like allways i spend time checking mild lift for the right length pushrods

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Originally Posted by 34_40

Pat McCarthy, is that a 302 SBF in that line-up? Roller Cam motor?

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no fords in that line up but here is some stroker Fords one 445CID

Bitchin'! I've been mulling over a 331 / 347 stroker and I thought I remembered you mentioned that someone left one behind or something like that....

nope he pick that one up 289 ford with a HYD Erson hyd roller kit in it i do work on fords :) i not sure if i have any photos of that one just a mild one nice street runner

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Originally Posted by pat mccarthy

nope he pick that one up 289 ford with a HYD Erson hyd roller kit in it i do work on fords :) i not sure if i have any photos of that one just a mild one nice street runner

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No sweat. I've been thinking is all!

what happened to 70chevybb? He has not replied since told the 6272292 heads were not 119cc chambers. I looked up some info from other websites they are open chamber and listed anywhere from 110 cc to 111cc. Intake and exhaust are 2.06/1.72.

i built many of them heads a cc them there abit more then 110 stock valves are 2.06/1.72 many times they do not say that size

I'm still here. I had an old friend give me a 454 and am now going to switch from the 402. I cc'd the 292 heads and sthay are 119cc the best I can tell. The 454 heads are 110 cc which will give me the copression ratio I need. I am still a ways from needing a running engine so It will be a slow build. I am rebuilding the cab of my truck right now. I have the frame fully restored. I will post some pics soon.

Thanks, Wes

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Originally Posted by 70chevybb

I'm still here. I had an old friend give me a 454 and am now going to switch from the 402. I cc'd the 292 heads and sthay are 119cc the best I can tell. The 454 heads are 110 cc which will give me the copression ratio I need. I am still a ways from needing a running engine so It will be a slow build. I am rebuilding the cab of my truck right now. I have the frame fully restored. I will post some pics soon.

Thanks, Wes

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sure like to know how you cc a head from GM there is no way it.s 119 ? at best 116cc . i used this head for over 20 years .the ones i built that were 292 casting i had on my mill and cut to a cc chamber i wanted .they never started at 119

I have used the 241,820, and 292 casting heads. All are similar chamber shape ( xtra exhaust shrouding) and all that I have measured are as Pat has stated, 113cc. I have the 292 casting on a 30 over 402. I pocket ported them and added the larger 1.88 exhaust valves. (11/32 back cut/ stainless). They work real well with the current set up. Next week i am pulling them to add different springs as I am switching out the flat tappet cam in favor of Howards pn 12315-10 camshaft. (227/227/.555/.555 110). Its difficult to make compression out of these 402s. I am going to cut .015 off the heads and use the Mr. Gasket .019 head gasket. It should put me about 9.2 to 1 with the KB160 and i'm .020 in the hole. This compression should be fine for this cam. Good luck with your build...

I have given up on the 402. I have taken the 454 to the machine shop. I will be going with the 781 heads and am having 2.19 and 1.88 vales cut in. The speed pro pistons have a .210 dome and will give me 9.77 to 1. My crank will be polished and will use pat's recommendation for a roller cam and rockers. It will be a slow build as I have alot of truck work to do.

Wes

It looks as my block will need to be bored.060. I will now have a final comp ratio of 10 to 1. Is still a good sreetable ratio or should I loer it?

Wes

yep if you run good gas

Very nice work Pat. but I expected nothing less!

I found a set of 049 heads that have had hard seats on both intake and exhaust. They were upgraded to the 2.19 and 1.88.
I can pick them up for 300.00. Are the 049's as good as the 292's or 781's .

Wes

should be no need to seat the intake side of the head when cutting it to a 2.190 intake are you sure they have seats on the intake side ? the 049 and 781 are about the same head

I am going to go look at them friday. The person said they had seats put in. He said something about having them interlocked because they touch in the middle. He claims that he drove less than 1000 miles on the heads before he pulled them and switched to rectangled port heads. He also told me the name of the local machine shop that did the work so I could verify most of his info. Are they worth 300.00 ??? Is it a big issue to have hard intake seats??

Thanks, Wes

yes the seat would have to interlock . why did they need intake seats ? only time you need to do this is if the heads are cracked or the intake seat were pounded threw the head and pulling the valve threw the head . a head with seats in it self is not bad put in right . But heads with all seats in them sound like there used up ?

I think I will pass by your comments pat. I will just stick with up grading my heads.