Head casting numbers...HELP plz

[fdcutlass]

from what im reading the common double hump heads had the same size chamber as the 441x's that i have. Will I gain anything by going to the double hump?

 

[86 Grand prix]

There is more to heads than just chamber size. Look at valve size, port sizes and the design of the ports and chambers. There is also a lot of difference in the old heads having much more metal in them and resistance to cracking. Pick up and old SBC head and then a mid 80's head.

 

[crotchss]

You can drill a set of vortec heads for the old bolt pattern, I have done it many times with no problems. The vortec head number to look for is 062. They will out flow any old style factory head because of its more efficient design. You can pick up sets of them cheap.

 

[lilbowtie]

I know you are tring to budget build but what is your final goal you want to achieve. It's the whole package for it to be happy.

 

[fdcutlass]

Ok so what type of vehicle should I look for to find the best vortec heads? Do I just drill for the bolt holes? My goal with my car is to be around 400hp give or take 25hp. I know it wont be a drag strip demon I just want a fun daily driver. Its an 86 olds cutlass supreme with a sbc in it. I bought this car to keep it off the stock car track. I over paid for it actually because around my area thats what everybody does with g body's. It had the sbc in it when i bought it along with a weiland intake and an edelbrock 650cfm carb. I just purchased a lunati voodoo cam and a 3.73 posi rear end. I found a 350 rocket in my yard so I am in the process of pulling that out to build and put in my olds. The rocket WILL be 425hp or so when im done with that but my wife and I are expecting our first child so it will be a slow build. Right now I just want this sbc to eat up all the ricers around here, I am so sick of hearing their crap. I am looking into the factory heads since they are free to me and i have access to them. I figure with the cam I'd try to help it breath a little better. Thanks for all the help.

 

[86 Grand prix]

1996-2002 Chevrolet trucks, Tahoes ect. They only came in trucks. Look at the rear of the block behind the intake and make sure it is a 5.7. That will be cast in the block. Check the heads for the casting number. Only the HD trucks came with the 906 heads.

 

[fdcutlass]

That's the era you'd most likely find the awful 882 head. Huge combustion chambers (low compression), prone to cracking, and lousy flow. It does nothing well except to serve as a doorstop. This just might be the worst head Chevy ever bolted to a 350.

Forgot to mention a thank you for stopping me from making a huge mistake. Everybodies input is greatly appreciated.

 

[fdcutlass]

1996-2002 Chevrolet trucks, Tahoes ect. They only came in trucks. Look at the rear of the block behind the intake and make sure it is a 5.7. That will be cast in the block. Check the heads for the casting number. Only the HD trucks came with the 906 heads.

So when you say the HD trucks are you talking about the 2500hd's with the 6.0L? or just a heavy half? And you say 96-02 but what about the 99 and up's that switched to the 5.3L engines? are those heads still ok? I have a 1999 suburban with a vortech 350 sitting in my yard, would that make a good canidate for heads?

 

[oldtinsmith]

Vortec heads use technology from about 15 years ago, while the older double-hump (fuelie) heads use technology from almost 50 years ago! I'm not saying the fuelie heads can't make a good performance street engine (I have a set of 186's on a '77 350 sbc), I,m just saying the vortec's will serve you better for what you're wanting to build. ...Camel hump heads: 3782461, '64-'66/327 sbc, no accessory holes, 160/62cc port volumes, 62cc chamber. ...3782461X, '60-'63/283-327sbc, no accessory holes, larger 172/64cc port volumes, 62cc chamber. ...3890462, '66-'67/ 302-327-350 sbc, no accessory holes, 64cc chamber. ...3917291, '67-'68/302-327-350 sbc, no accessory holes, 64cc chamber. ...3917292, '68 sbc, no accessory holes, 64cc chamber. ...3927186, '69-'70/302-350 sbc, WITH accessory holes, 64cc chamber. ...3927, '69-'70/ 350 sbc, WITH accessory holes, 64cc chamber. ...3973414, '70/350 LT1 (370HP) sbc, no accessory holes, 64cc chamber. ...3991492, '70/350 LT1 sbc, WITH accessory holes, 64cc chamber/straight plugs. ...3991492, '70-up/ over the counter head. ......Right angle casting mark heads: 3947040, '68/327 sbc, good HP head used in trucks, no accessory holes, 64cc chamber. ...3947041, '69-'70/302-350 sbc, good HP head, WITH accessory holes, 64cc chamber. ...3947041X, '69-'70/302-350 sbc, good HP head, 165cc intake port, WITH accessory holes, 64cc chambers. ......Heads that came with 2.02/1.6 valves came with (usually) screw in rocker studs and guide plates.

I'll be 67 years old in 8 days and I must tell you that I haven,t done research like this in years!!! I need a nap !

Doug

 

[86 Grand prix]

1996-1999 in regular trucks and up to 2002 in large vans. The 2500HD trucks up to 1999 could have the 5.7L Vortec but it was a HD engine with four bolt mains and hardened valve seats. That is what my engine came from. Early reports say that the 906 heads did not flow as well but just as many reports now say no noticable difference.