Hello, I finally bought a 350 for my 87 camaro! Just got home to be more exact. Anyway the motor is out of a 1978 truck I believe. Built at flint. Its a four bolt main too! And only paid $100 for it and the two heads I am about to list.

Both heads will be redone, IF I can use them both..guy said both were on the block, and they even have the samegasket so...I just never thought you could do this..What do you guys think?

Head one, 3991492...Double hump head i think...

Head two, 3973370...Also double hump I believe, BUT says it is a more desirable head, and is slightly larger than the other double hump heads.

Both heads are a 2.02 with the 1.6 exhaust, but would it matter that one is slightly larger than the other? Or is it really slightly larger or not?

Again, if you guys say its cool to run them both on the same 350, i will have them cleaned up. I am gonna get a good cam and intake to try to get around 350-400 hp. The rods and crank is forged so i am good there. And thinkin to have the pistons replaced as well. Right now the motor has been sittin 3 years in dudes garage. But the cross thaching is still there! LOL Guy ran it for about a month, then removed it and its sat ever since. I got the crank, pistons and rods, cam thats in it..and both those heads and a oil pan. Thinking the $100 I spent is a killer deal. Thanks everyone who replies with help..

 

Sounds like a good way to blow a motor to pieces, but i have no science as to why. Intrested to know how it goes

 

EXACTLY what i was thinking. I guess if nothing else when i talk to the machine guy tomorrow he will be able to tell me one way or the other..

 

It reminds me of wankels, never last because of uneven forces etc,(I LOOOOVE rotarys but its just a fact) so idk man, be careful and take good care of that baby

 

oh yeah i will! I just asked cause BOTH are of course 2.02intakes, with 1.6 exhaust..I just Don't know..lol. Hopefully one of you guys will!

 

Both of those heads are good, and one might be a little better than the other. The 3991492 heads came on the 1970 LT-1 (Camaro/Vette), with straight plugs, screw in studs, and guide plates. After that, they were an over the counter replacement head, available in either a straight or angle plug version.
The 3973370 heads are just like the 492 castings, application was 1969-70 300 h.p. They were also an over the counter head only.
Both heads have 64 cc combustion chambers. The 492's have 2.02/1.60 valves. The 370's came with 1.94/1.50 valves, but they may have also been available with 2.20/1.94 valves (not positive tho). Measure your valves closely to be sure, but they can be machined for the bigger valves if they're not now.
Are you going to injure the engine using the two different heads? Nope, not at all. But for best performance, you'd want to make sure the valves are the same size between the two heads.

 

DUDE thanks brother! Sounds like you really know your stuff! When i head over to the machine shop here in a bit I will have them measured. Glad to hear they are good heads!!! And to me, hi performance...lol. Like i said before, I am looking for 350-400hp, and all the ground shaking torque I can mangae out of it..lol. Thinking these along with a good cam should get me right in that sweet spot..what do you think?

 

You can easily hit your hp goal with those heads you have, and a little p&p work done up right won't do them any harm either. They're not nearly as good as what you can now buy in the aftermarket or even re-worked vortec heads for that matter, but that would throw your wallet into a totally different budget range.

 

Well, bad news, and good news I guess...

The heads are ok. No real problem there. Guy at the machine shop said i could use both of them without a hitch. They are both the 2.02 heads. Double hump.
But that they do need some work. He says that to fix them up right, and run them without fear of them failing , that i should just sell them and get a set of newer vortech heads, or just get new aftermarket aluminum heads. Yeah, this sucks BAD! He said the difference between getting these heads up and going and a set of brand new chinese heads, would be so close I may as well go with the new heads. Only like a $400 diff..
Here I thought I was doing good! Now I see this crap and frankly my heart dropped. Not only that he said I did a great job on the motor..but that I should have been looking for a 87 or so old vortec that way I would already have a roller cam setup or somthing like that.
He says going at it like I want, 350-400hp is easy to do...but that I will need to install a roller cam. And rockers, or something like that. Sorry, new to engine's so I may be getting some of this mixed up. Point is, my $1200 or so rebuild just went through the roof to $2500-$3000.

 

I can't believe a machine shop is going to recommend you use some Chinese heads. Did he happen to mention a brand name, like are they the Procomp heads that Summit and Jegs sells? If so, do a google search about the build quality of those, and you'll be searching for something else pretty quickly. If you're seriously leaning towards going with aluminum heads, AFR are the ones to get.