Thread: 402 heads

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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 .

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 .

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

Originally Posted by 34_40

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

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