So bear with me. I just recieved a donated set of 350 heads for an SBC. I've yet to decide wether or not I want to use them, but I'm hoping you guys can point the way. These are a set of of early 70's, 3998993 heads, each chamber is 76cc and the valve sizes listed, yet unconfirmed, should be 1.72/1.50 in and 1.94/1.50 out. I've quickly researched and found these are kind of "rated" as a low performance head. So I guess my ultimate question is, would a great cam pull power out of these and make them acceptable heads? I'm putting this in my 53 chevy and it's just a cruiser, I won't be dragging in it or anything. Will I be dissapointed using these? Thanks in advance, Geoff
Depends on your definition of acceptable. Those are "Mexico" heads, aren't they? They should pull the car around for cruising and what not, but I don't think they are a performance head. If they are in good shape, and all you want is to drive the car around, I'd use 'em.
What does your existing bottom end look like? Are you doing a fresh rebuild of the entire engines or are you just changing heads and cam? How many miles are on it already? The 76 CC - means low compression with stock pistons. A small cam with a 1-5K range will be better than a stock cam etc.
I didn't spot a Heche en Mexico cast, but that's not to say I looked very closely.... They may be, and if so, are there any quality control issues I should worry about? They are in need of a valve job to be sure. I just don't want to dump money into a set if they are destinet to dissapoint. The block is a single piece 4 bolt. We were going to find a good match to these as far as pistons and crank goes. But to answer the question, yeah, I just plan on cruising around town. ANy suggestions on a cam? Geoff
hmmm...not sure what you mean by that! the intake valves on the 350 2bbl heads were 1.72, on the 4bbl "normal" heads they were 1.94, both use 1.50 exhaust valves. I'm pretty sure the 993 uses the 1.94 valves, you can measure them easily. like he said, they're made in Mexico...still, the basic head design is ok, I'd use it with a smallish cam, do just a little clean up porting and a good valve job, and probably be happy with them in a daily driver.
depends how broke you are. after going through a set of heads to make sure the valves seat well, seals are good and springs haven't softened up it is usually $350/pr from a machine shop. cast iron performance heads can be had for $500 or less and you get the benefit of new castings with improved flow and 2.02/1.60 valves, because you will want to go faster eventually. http://www.midwestmotorsportsinc.com/order_sub.php?id=15
stick with a mild, or rv cam unless you plan on higher compression and a 650+ carb. around .495 lift would be maximum, keep it closer to .470 to prevent coil bind on stock springs.
Yeah, I probably wouldn't use 'em if they still had to go to the machine shop. You can get better heads for not much more than the machine bill is gonna cost.
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