fatboy999

I have a 1966 427 CID engine and want to swap intakes, but don't know if it has square or oval ports. How can I tell without pulling the intake? The stamping numbers are: T09011M 185402026

L88Plus

Pull a valve cover and post the casting number here. Should be 6 - 8 digits, all numbers. If it's a 'vette engine, my $1 says they're rectangular.

MrForce

Is there a casting number on the intake?

fatboy999

Sorry guys, I don't have the car here. I don't have the carhere, it's 2 1/2 hours away. Just got the engine stamping numbers when saw it the last time.

restoman1

Well, going by the numbers, you don't have a 1966 427, you have a 1968 427/400 from a 1968 Corvette. If the heads and intake are original, then you have oval ports.

T09011M is probably T0901IM which is a 1968 L36/L68 assembled on September 1st, 1967. The VIN is probably 18S402026 which is a 1968 Corvette assembled at the St. Louis, MO plant.

Ed

69 Chevy

If I remember my rat motors correctly, oval port heads will have PASS cast into them between the valve springs. Rectangular ports will have HI-PERF there instead.

Rebelrob

yep, my old LS7 454 cast heads were rect ports and they had
HI-PERF stamped on them. My current block also has HI-PERF PASS stamped on the block if I remember correctly.

d555

It is easy to tell if the head is a rect port or oval by the single Hump that is cast in to the front of the head on all Big Bock Heads from this time period, 1965-1972

This single Hump is cast at the end of the heads, where the top mold and bottom mold come together. At the parting line. All heads of this era had them. NO hump? OVAL port!
Do not confuse with a sloped off rectangular cast in to the front as this is different.

Only the head casting numbers will tell for sure.

Dave