I just took apart a 1966 Impala HCH code 327 that I know nothing about. It had 3973487 heads on it so I knew it was not stock. It has been a long time since I had a 327. The crank is forged and has some letters stamped on it. One rod cap has something epoxied to it. I suppose it could be for balancing but looks odd. The turning on the crank looks rough also. It is standard bore with stock pistons and bore. As I looked at the block it looks like it was ground on to make it smooth? Anyone know anything about this?
well the numbers on the crank are probably just part numbers, but almost all of those early small journal cranks are forged for the most part. Yeah the rod cap is odd and no clue why they would do that. Someone might have thought of using the block for a show car and wanted a smooth block.
Who knows what speed secrets lurk in the minds of men? Or, maybe the grinding was an overzealous removal of casting flash.
Probably just deburred the block real good. Internally it helps with oil flow also adds strength by eliminating all the sharp casting edges. That rod just looksl like paint on it. Idk??? Sent from my iPhone using H.A.M.B.
Never seen a coin/washer/slug epoxied to anything like that (rod cap)! Can't even begin to guess at the clearancing inside the block webbing; only whoever did it really knows. Could have been someone cleaning up some damage after throwing a rod? The rear main webbing looks almost like "repair work" (???). The rod throw looks like bearing trash to me. Early 70's "performance heads". Collage of parts? I am Butch/56sedandelivery.
I just looked up the 3973487 head casting numbers.... Looks like they were used on the '71-'72 LT-1 350s... That depends on the valve sizes... The chambers are 75cc... Question is... Do those heads have the 2.020" intake valves????? How's about a picture of the chambers???....
HC is a 66 full size car 327 275 hp. The H after it means it came with a Holley carb, I think. The rod cap looks like it's probably a factory replacement rod, that was never machined for balance. The stamps on the crank, are probably from a factory operation when it was being machined or balanced or assembled. The smoothing was probably done by a misguided/bored hot rodder a long time ago.
They do not have the big valves. Some of the intakes are worn way into the seats. The ones with an X after the casting number are the good ones.
It is a mess. I am leaning toward a rod being thrown and somehow the person thought that gluing that slug on there was going to keep it in balance. Another strange thing is the bores are standard, no ridge, and hone marks can clearly be seen. The block is on the way to the scrapper and probably the heads. Thanks everyone.
487 heads came as early 70's high performance heads, and are either 1.94/1.50, or 2.02/1.6 valves. So unless someone upgraded or rebuilt them they can be either. Since they didn't have hardened seats, if rebuilt people usually at least put 2.02" intake valves in, and switch to stainless valves also. I have the 487X version, and the machine shop put all new hardened seats, stainless valves, iron guides, and upgraded mine to 2.02/1.60 These heads have very good flow rates at around 180. These also are built before they began making thin castings around 1977, so don't have cracking issues.
I have to wonder if the cleanup grinding was due to a rod letting go? Which also may help explain the oddball rod? That rear shot looks very rough, like that was cylinder that let loose. I don't think the block is necessarily scrap, but certainly would not recommend for hot rod engine where performance upgrades are likely. The heads with the valve seat recession probably cost more to save vs replacement with better heads. Sent from my SM-A102U using The H.A.M.B. mobile app
That is what I had read but the X version seems to be preferred. The casting dates are only 2 days apart so I put them on Ebay to see if some restorer needing the specific date code might invest the money in them. Thanks again!
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