BBC head Q's - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Snowbound · 02-19-2003, 01:13 PM

Will the tall deck heads from 366/427 Trucks fit a regular 454 block? And would they be any better than the stock 1981 heads? I don't have any casting numbers, but the Truck heads are from about '68 or so. I'm looking for a cheap way to hop up this 454.

Desert Rat or any of you other BB guru's???????

Brian

JimKshortstep4x4 · 02-19-2003, 02:12 PM

The heads will fit, but I would be concerned about the valve seats
and the volume of the chambers. Some truck heads had small valves, also.

Your power may go down instead of up!

jim

Snowbound · 02-19-2003, 10:15 PM

I'll have to check the casting #'s again. From what I read on Mortec, the same castings were used on 396, 366T, 427 and 427T. Maybe just the valve sizes were different? I think the castings ended 059 and 060 or something, but I couldn't find anything that matched up.

Brian

spinning wheels · 02-19-2003, 10:24 PM

Before you change heads, make sure you have the correct manifold. Round port heads with round port manifold. Square ports with, well you get the point. Also, some heads are closed chamber heads. Higher compression. Which means you would need to run Premium gas. Right now at over 2 bucks a gallon in the US. Ouch! that would hurt on a road trip.
Most likely, the truck heads have a lower cc flow, so you may not see a performance increase. You would get some good torque and bottom end tho.

Dan72cst · 02-19-2003, 11:33 PM

I'm not a "guru" but I believe they will bolt onto your '81 block. BUT MAKE SURE YOU HAVE THE CORRECT PISTONS. Big blocks have closed chamber heads and open chamber heads. They have to use pistons designed for closed chamber or open chamber. NO if's and's or but's !!!!!! I think GM changed from closed chamber to open chambers in 70 or 71 except for the vette changed to open chambers in 69 or so. You'll have to ask a guru for exact.

Snowbound · 02-20-2003, 12:03 PM

Thanks guys,

I'll get the casting #'s to be sure. The '81 454 is a low mile bone stock engine in a 1 ton camper special, so I assume it has flat top pistons?

Maybe I should leave the engine alone until I get a posi unit under the rear.

Probably more torque than I can handle, even stock.

Brian

02-19-2003, 01:13 PM	#1
Snowbound Registered User Join Date: Aug 2002 Location: Westbank, BC Posts: 401	BBC head Q's Will the tall deck heads from 366/427 Trucks fit a regular 454 block? And would they be any better than the stock 1981 heads? I don't have any casting numbers, but the Truck heads are from about '68 or so. I'm looking for a cheap way to hop up this 454. Desert Rat or any of you other BB guru's??????? Brian __________________ 1965 Chevy Short Box Stepside, 230 - 3 speed, 4:11 gears, original paint rust free survivor. Now sporting a 383 SBC and TKO-600

02-19-2003, 10:15 PM	#3
Snowbound Registered User Join Date: Aug 2002 Location: Westbank, BC Posts: 401	I'll have to check the casting #'s again. From what I read on Mortec, the same castings were used on 396, 366T, 427 and 427T. Maybe just the valve sizes were different? I think the castings ended 059 and 060 or something, but I couldn't find anything that matched up. Brian __________________ 1965 Chevy Short Box Stepside, 230 - 3 speed, 4:11 gears, original paint rust free survivor. Now sporting a 383 SBC and TKO-600

02-19-2003, 10:24 PM	#4
spinning wheels Registered User Join Date: Sep 2001 Location: Hacienda Heights, California USA Posts: 474	Before you change heads, make sure you have the correct manifold. Round port heads with round port manifold. Square ports with, well you get the point. Also, some heads are closed chamber heads. Higher compression. Which means you would need to run Premium gas. Right now at over 2 bucks a gallon in the US. Ouch! that would hurt on a road trip. Most likely, the truck heads have a lower cc flow, so you may not see a performance increase. You would get some good torque and bottom end tho. __________________ '72 GMC custom camper 350/350

02-19-2003, 11:33 PM	#5
Dan72cst Registered User Join Date: Feb 2001 Location: Lake Stevens,WA 98258 North of Seattle Posts: 833	I'm not a "guru" but I believe they will bolt onto your '81 block. BUT MAKE SURE YOU HAVE THE CORRECT PISTONS. Big blocks have closed chamber heads and open chamber heads. They have to use pistons designed for closed chamber or open chamber. NO if's and's or but's !!!!!! I think GM changed from closed chamber to open chambers in 70 or 71 except for the vette changed to open chambers in 69 or so. You'll have to ask a guru for exact. __________________ Marysville, WA (Dan72cst@hotmail.com) 72 4wd Blazer CST 350/350 72 4wd Chevy LWB 350/350 68 2wd Chevy LWB 327/400

02-20-2003, 12:03 PM	#6
Snowbound Registered User Join Date: Aug 2002 Location: Westbank, BC Posts: 401	Thanks guys, I'll get the casting #'s to be sure. The '81 454 is a low mile bone stock engine in a 1 ton camper special, so I assume it has flat top pistons? Maybe I should leave the engine alone until I get a posi unit under the rear. Probably more torque than I can handle, even stock. Brian __________________ 1965 Chevy Short Box Stepside, 230 - 3 speed, 4:11 gears, original paint rust free survivor. Now sporting a 383 SBC and TKO-600

02-19-2003, 02:12 PM	#2
JimKshortstep4x4 Senior Member Join Date: Jul 2001 Location: Muskegon,MI,USA Posts: 6,026	The heads will fit, but I would be concerned about the valve seats and the volume of the chambers. Some truck heads had small valves, also. Your power may go down instead of up! jim



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