66 427 390hp

[Pete M.]

1)

2)Is there any distinction in the cylinder heads between 325, 350 HP 396 motor and the 390 HP 427 motor? Should either motors have HI PERF coded into the heads as you would see in the block? Reason I ask is that I thought I once saw a 390 HP 427 that had HI PERF coded into the heads, but not sure. thanks for any feedback

[Steven S.]

Re: 66 427 390hp

Dates sound good for an April car, not unusual to see two different dates on heads, and that head was the same as what was used on the 396's as you mentioned.

[Pete M.]

Re: 66 427 390hp

thanks steven, should the heads be coded with HI PERF like the block is? thank you

[Ronald L.]

Re: 66 427 390hp

Pete I also have an April 66 390 car. I would recommend gathering all the information on the engine possible.
Heads, intake, block, exhaust & water pump.

And then we need to see that engine stamp pad - if it was not cleaned in a deck-rebuild.

Yes they should have Hi Perf in them.

[Pete M.]

Re: 66 427 390hp

thanks Ronald, engine stamp pad, intake, exhaust, block, trans all seem to check out. but now i'm concerned i've got a problem with heads, since as far as i can tell they're not coded with HI PERF. heads appear to have correct part no. and date code, but i'm not seeing HI PERF. the block is coded with HI PERF. thanks again

[Ronald L.]

Re: 66 427 390hp

Pete,
Hard to help with out the detail and of course pics help too. Make sure the part number is in the head. I have pics of mine we can find them and compare to your motor once we see more of what you have. If these prove to be wrong, one of two guys I know have thousands of these, good chance to get something correct.

But here's my 2 cents. 32 years ago I bought a 66 390 Dec 13 VIN car and I distinctly recall (no pictures) that all the casting dates on that motor were within 3 weeks of each other in September. When I restored that car, I tool the water pump to a rebuilder and waited and watched for more than 4 hours as that went through the process so as to not lose even a screw.

This late April car has the same tight cast components.

Shoot an email if you don't want to post all the detail.

[Joe L.]

Re: 66 427 390hp

thanks Ronald, engine stamp pad, intake, exhaust, block, trans all seem to check out. but now i'm concerned i've got a problem with heads, since as far as i can tell they're not coded with HI PERF. heads appear to have correct part no. and date code, but i'm not seeing HI PERF. the block is coded with HI PERF. thanks again

Pete------


If the heads are of the correct casting number, 3872702, then don't be concerned about whether they are embossed "HI PERF", or not. There's no guarantee that every foundry pattern ever used for the 3872702 cylinder head was embossed "HI PERF".

The same 3872702 cylinder head was used for all 1966 oval port applications including 325 and 360 HP 396 cid engines used in Chevelles and passenger cars as well as 390 HP 427 engines used in Corvettes and passenger cars.

[Pete M.]

Re: 66 427 390hp

thanks joe, much appreciated

[Pete M.]

Re: 66 427 390hp

thanks just sent you an email