[Skip Fix]

Or some mini pop up pistons.

[KJ223]

Ok what would be some good budget options for head numbers that preferably just bolt on with minimal modifications to anything else, if that’s even possible? I’ve seen the edelbrock aluminum heads but I certainly don’t have the $2000 to throw at those, even if I did it seems wasteful for a 350.

[gtospieg]

#47 and #17 were stock heads on the 350 in 68 and 69. Either one of those would get you where you want to go.

[Formulas]

#11s from 1970 @ around 82-85 CCs will also work better than 6X4, mill any 68-70 350 head .020 to get even more of a bump without any drawbacks

[78w72]

Originally Posted by KJ223

What would having them milled .030 do? I looked at the chart and I see it’ll reduce the combustion chamber but what does that do to the compression ratio, like how much does it increase by? I’m still trying to learn all this. I’m at 7.6:1 right now based on other posts and previous replies, what would it change to 8:1, 9:1?

You can use this calculator or others like it to get a pretty accurate compression number if you know the specifics of the parts in the motor. You can mill more than .030 off the heads if done right. 6x-8 heads are larger CC than 6x-4.

http://www.wallaceracing.com/cr_test2.php

[PunchT37]

Or some 16 heads from a `70 400. High compress and 1.96 valves. Good for a 350.

I think those heads are around 75cc.

[MarkS57]

The 68 17's are fairly inexpensive and available in market. Only thing about the 70 and earlier heads is it's best to use the alternator & PS pump mounts from a 1970 engine. Not too difficult to find.

[PunchT37]

Originally Posted by MarkS57

The 68 17's are fairly inexpensive and available in market. Only thing about the 70 and earlier heads is it's best to use the alternator & PS pump mounts from a 1970 engine. Not too difficult to find.

There`s some 17`s for sale in the parts section. But, shipping could be a killer.

[PunchT37]

I know a member here who has a set of those 16`s he might let go. Off a `70 YD 400. We`re using that block for a stroker 428.

[SD455DJ]

Originally Posted by PunchT37

Or some 16 heads from a `70 400. High compress and 1.96 valves. Good for a 350.

I think those heads are around 75cc.

I have those heads (#16) on a 1970 XV code 330hp 400 (out of a Catalina) and they cc'd at 82-83 cc's from the factory. A minimal cut to true them up took them down to 78 cc's. The 400 was advertised/rated at 10.0 to 1 compression and in a .030" over 400 with pistons down .0015" in the hole with .039" gaskets, it measured 9.94 to 1 compression.

I'm not sure what cc's the 1970 #11 heads are, but they were installed on both the 350's and XX code 400 2-bbl's, both factory advertised at 8.8 to 1 compression. I believe the 400 is closer to reality and most likely 8.3 to 1 compression, and the 350's are more like 7.8 compression. Definitely find a head with no more than 80 cc chambers like the #16's. They are easy to find and a great start to upgrade.

Dennis

[PunchT37]

Originally Posted by SD455DJ

I have those heads (#16) on a 1970 XV code 330hp 400 (out of a Catalina) and they cc'd at 82-83 cc's from the factory. A minimal cut to true them up took them down to 78 cc's. The 400 was advertised/rated at 10.0 to 1 compression and in a .030" over 400 with pistons down .0015" in the hole with .039" gaskets, it measured 9.94 to 1 compression.

I'm not sure what cc's the 1970 #11 heads are, but they were installed on both the 350's and XX code 400 2-bbl's, both factory advertised at 8.8 to 1 compression. I believe the 400 is closer to reality and most likely 8.3 to 1 compression, and the 350's are more like 7.8 compression. Definitely find a head with no more than 80 cc chambers like the #16's. They are easy to find and a great start to upgrade.

Dennis

This goes against the grain but, I know a guy with a `70 Forumula. All original. It`s got a YS 400, 330hp with 16 heads. Go figure. It`s supposed to have 13`s.

[SD455DJ]

Originally Posted by PunchT37

This goes against the grain but, I know a guy with a `70 Forumula. All original. It`s got a YS 400, 330hp with 16 heads. Go figure. It`s supposed to have 13`s.

Hmm...I wonder if they are the '68 variety (be curious what the casting dates are), or warranty work by a far-sighted Pontiac service tech...?

Dennis

[PunchT37]

Could be. Been a while since I saw it. Here it is;

That car was bought by him new. He was my old boss. No warranty work. The car only has 52,000 miles. All his cars are spotless. He`s got an `89 Turbo T/A WITHOUT T tops and the pace car decals. He had a `77 T/A without the bird on the hood and a 1/3 gold vinyl top. White T/A with gold top. A mirror of the Formula.

[SD455DJ]

Originally Posted by PunchT37

Could be. Been a while since I saw it. Here it is;

Nice! Looks like Palomino Copper with a white vinyl top?

Dennis

[PunchT37]

Originally Posted by SD455DJ

Nice! Looks like Palomino Copper with a white vinyl top?

Dennis

Yep.

He had an `83 or `84 Eldorado with a stainless roof. No paint. He always finds odd cars.

[gtospieg]

KJ223...let people know where you're located. Maybe someone close to you has a set of these heads so you can pick them up and avoid shipping$$$$.

[KJ223]

Originally Posted by gtospieg

KJ223...let people know where you're located. Maybe someone close to you has a set of these heads so you can pick them up and avoid shipping$$$$.

I’m in the Columbus Ohio area, about 25 minutes east.

[Formulas]

Iam less than 2 hours from you near Gallipolis OH

i have #47s #11s on the shelf

#47s <used> lightly ported stock valves bronze guides drilled for 1/2 base 7/16 studs. insert hardenedex valve seats milled approx .020

#11s bone stock dissasembled untouched take offs

both original california non rust buckets

not looking to sell but realise i will probably never use them again

[1980Ttops]

KJ223, I am in Otway Ohio. If you haven't found a set of heads yet, I have a set of 1970 #16 & a set of 1969 #46 heads. I would trade a set for your 6X-4 heads. The 69 #46 heads are 74cc & the 70 #16 heads are 78cc. I'm in the Circleville & Logan area often. Text or call directly at 740-three 41-3 zero 96

[steve25]

Keep in mind here folks that all the alternative heads posted about here do not have screw in rocker studs which you need to run more then .420”

With the cost these days of converting heads over to screw in studs I would do this.

If your going for new pistons anyway then get some mini pop up’s and run the 6X heads.

Besides the screw in studs they have the benefit of smaller exh cross over passages ( less performance degrading interaction between center cylinders ) then the early heads and the intake port flows real well since they have a tad bigger port area,and they have the coolant temp sender where it should be in the outer wall of the head.