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1965 327/300. Engine Casting # 3858180. Corvette Black Book says the casting should be 3782870 for a 327. Does this mean the 327 in my car isn't original?
HCH would seem to indicate a 1966 327 275 hp engine with a Holley 4-barrel and a power glide, from a passenger vehicle.
Check out the Lime engine book posted above as a sticky.
Good luck... GUSTO
And the "T" prefix indicates a Tonwanda built block. All Corvettes used Flint built small blocks in the C1-C2 cars. For 1965 model cars, these Flint blocks start with prefix "F".
I wouldn't exactly call it a Heinz 57, it is essentially the same engine that would have come in a '66 Corvette with the 327-300hp engine. Performance wise, it should feel right at home in your car. Do you have any idea what engine actually came in your car? What does the redline on your tachometer read?
Post the part numbers on your heads and we'll be able to tell you even more. In fact just pull a valve cover and post a few pictures of the heads...
@GUSTO14 Man thanks for sticking with me on this. So I pulled the valve cover and snapped some shots. I got this car in May when my dad passed. Never been a car guy and now I'm hooked. So check these out and let me know what you see... and THANK YOU!
Tach VIN and Something Passenger Side 3782461 G31 5 3782461 GM 3 inside valve cover 3767493
Just a note on the aluminum valve covers. They are correct for the year but not a 300 HP engine. They are in nice shape and don't have the casting flaw.
Only the higher performance engines had them. Take care of them as they are valuable.
If it is the original engine the pad in front of the passenger side head will have the numbers that tell the information .
Since we know the engine is not original it is hard to know. Your heads seem to be correct for a 65 engine, This suggests that the heads could be original.
The only way to know the true HP would be to disassemble the engine and check the internal components . Do you know if the cam is a hydraulic or solid ?
Last edited by silver837; Sep 13, 2022 at 10:51 AM.
Larry is correct, the HCH suffix indicates the block is a 275 hp, 327 used in a 1966 Chevrolet passenger car. The 275 hp engine was rated at 300hp when installed in the Corvette. I've heard this was attributed to the exhaust system in the Corvette and also that Chevrolet might have wanted it rated higher than the passenger car engine so the numbers were adjusted accordingly. Bottom line is they were essentially the same engine.
Your tachometer redline also indicates it goes with a 300hp 327, as do the cylinder heads. Based on all of that there is no reason yet identified to believe your car didn't come with a 300hp 327. Unless there is something wrong with the engine you have, or you just want to change it to something else, I'd say the engine you have is about as close to the original as you're going to get without a lot more information of the cars history and a whole lot of money.
At the very least enjoy the car for what it is and show it with pride. A 300hp 327 in the mid-year Corvette is no slouch!
If it is the original engine the pad in front of the passenger side head will have the numbers that tell the information .
Since we know the engine is not original it is hard to know. Your heads seem to be correct for a 65 engine, This suggests that the heads could be original.
The only way to know the true HP would be to disassemble the engine and check the internal components . Do you know if the cam is a hydraulic or solid ?
I don't know the answer to that. Outside of conversations I had with my dad, I don't have much to go on. Thank you!
Hey! I'm very proud of this bad boy. Its beautiful... I love it. I plan to learn as much as I can, take care of it and pass it along to my kids at some point. Thank you for all your help
Larry is correct, the HCH suffix indicates the block is a 275 hp, 327 used in a 1966 Chevrolet passenger car. The 275 hp engine was rated at 300hp when installed in the Corvette. I've heard this was attributed to the exhaust system in the Corvette and also that Chevrolet might have wanted it rated higher than the passenger car engine so the numbers were adjusted accordingly. Bottom line is they were essentially the same engine.
Your tachometer redline also indicates it goes with a 300hp 327, as do the cylinder heads. Based on all of that there is no reason yet identified to believe your car didn't come with a 300hp 327. Unless there is something wrong with the engine you have, or you just want to change it to something else, I'd say the engine you have is about as close to the original as you're going to get without a lot more information of the cars history and a whole lot of money.
At the very least enjoy the car for what it is and show it with pride. A 300hp 327 in the mid-year Corvette is no slouch!
Good luck... GUSTO
@GUSTO14 So I figured I'd cleanup and reseal the covers since I had one of them off... and I find this. Doubt it means much but funny nonetheless. - Randy.
Another point on original Valve covers. They were not polished in any way. They do look nice that way but will decrease the value to someone seeking originality.
Looks like the 3858180* did have some built in Tonawanda. @GUSTO14@Powershift Does this change your view that this could be a 65 and not a 66?
Oh well... casting on intake Manifold: 3872783 GM1 - 1966 Cast Iron 300HP 327.
Engine Casting Numbers
