Big block chevy bore/stroke number - The 1947 - Present Chevrolet & GMC Truck Message Board Network

Blue85 · 06-19-2004, 07:22 PM

I though I found a 454 but i ran the number and it ended being a 366, what us the difference between bore and stroke between the 2? Also, would the heads be the same?

**breeh** · 06-19-2004, 07:59 PM

A 454 and a 366 are completely different animals. The 366 has a taller deck. I think that the stroke on the 366 is a 3.76 but I am not positive.

jimfulco · 06-20-2004, 03:16 AM

366 bore is 3.94", stroke is 3.76". The following is from Mortec:

We are asked about the 366 BBC "tall deck" truck engines often. Unfortunately they are not worth using as a performance motor. Safe overbore is .060" and that doesn't make much. They can be stroked but then you can find pistons to match "off the shelf" and so custom pistons are required. You can "harvest" the heads, oil pan, valve covers, crank and rods from them to use on another larger bore Mark IV BBC. Otherwise, don't waste your time or money. The 366 makes a good low power heavy duty truck mule engine or an excellent boat anchor.

Blue85 · 06-22-2004, 12:20 AM

Will the 366 motor mounts work with a 454?

06-19-2004, 07:22 PM	#1
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,171	Big block chevy bore/stroke number I though I found a 454 but i ran the number and it ended being a 366, what us the difference between bore and stroke between the 2? Also, would the heads be the same? __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

06-19-2004, 07:59 PM	#2
breeh Recovering 67-72 Addict Join Date: Oct 2000 Location: North Bend, WA Posts: 1,788	A 454 and a 366 are completely different animals. The 366 has a taller deck. I think that the stroke on the 366 is a 3.76 but I am not positive. __________________ 68 Short Fleet 4x4; 427; BTO Level 3 700R4; NP205; Dana 60 front and rear; 4" lift with 35's; Disc brakes; AGR variable ratio steering; factory bucket seats; factory tach and tilt. "Friends call me cruzer cuz I like fast cars and fast women"

06-22-2004, 12:20 AM	#4
Blue85 Oilfield Trash Join Date: Sep 2003 Location: Raymore, Sk, Canada, Earth Posts: 3,171	Will the 366 motor mounts work with a 454? __________________ 14 Dodge 3500 Mega Cab 08 Dodge 3500 Mega Cab 87 Chev 3+3 4x4 80 GMC K10 High Sierra bone stock 70 Chevelle 350SS long term project 68 GMC 3ton Grain Truck/Garbage wagon 50 Pontiac 2 Door Coupe Project "I've got a shotgun rifle and a 4 wheel drive and a country boy can survive" Hank Jr.

06-20-2004, 03:16 AM	#3
jimfulco Registered User Join Date: May 2003 Location: Shreveport LA Posts: 3,170	366 bore is 3.94", stroke is 3.76". The following is from Mortec: We are asked about the 366 BBC "tall deck" truck engines often. Unfortunately they are not worth using as a performance motor. Safe overbore is .060" and that doesn't make much. They can be stroked but then you can find pistons to match "off the shelf" and so custom pistons are required. You can "harvest" the heads, oil pan, valve covers, crank and rods from them to use on another larger bore Mark IV BBC. Otherwise, don't waste your time or money. The 366 makes a good low power heavy duty truck mule engine or an excellent boat anchor.



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