mixing early/late BBC parts

Ken Haase · 04-22-2009, 02:59 PM

Is it possible to use MkIV ('86 vintage) heads on a Gen.6 block? I thought I remembered reading that there is a head gasket that would allow this without any fluid leaks. Thanks for any help.

Alan Roehrich · 04-22-2009, 06:05 PM

That's an "iffy" situation. FelPro makes a few gaskets, you need to call their tech line or look at a catalog.

Ken Haase · 04-22-2009, 06:47 PM

Thanks Alan. I was pretty sure you would know and also respond.
Ken

Mike Taylor 3601 · 04-22-2009, 07:02 PM

I know it can be done because I seen 502 blocks used to build 540's use aftermarket heads like Alan said
call fel pro tech line to get right gasket catalog has that info but is confusing so call them to verify.
Mike Taylor3601

Rich Biebel · 04-22-2009, 07:06 PM

That is definately no problem. I built a 502 for a bracket/street driven car and used a GenVI block with early oval port, closed chamber heads. I can't recall what head gasket I used but I belive it was a GM gasket. That engine is still going. It never had any problem and has run in the 9's after it was transplanted from a street car into a racecar. I got the info for what I needed and bought some parts from one of the GM Performance parts dealers thru their catalog. Pace Chevrolet. Scoggin Dickey is another good source. Lots of good info in those catalogs..........

Ken Haase · 04-23-2009, 12:18 PM

Thanks for the help guys. I'm trying to come up with a viable engine for my dually. My grand experiment with Rectangle port heads was a bust, even with revs of 3 grand plus. I should have known better; just gettin' stupider with old age. I now realize why the diesels are the engine of choice. I just can't afford one.

Alan Roehrich · 04-23-2009, 05:33 PM

Ken, the hot setup is the old closed chamber oval port heads, or the Vortec heads. About 96 to 100cc chamber, and 2.19 intake valves with 1.88 exhaust valves. If you can get 10:1 compression it will work fine. My old 454 had about 9.5:1 and it really wasn't enough, even though I went down in cam to a 218/.520. An all steel flat bed truck, with steel wheels and no overdrive it would get 12-14 loaded or not, and pull 20K pounds with ease. With the air on. Of course, with Camaro headers, 3" pipes, and huge mufflers, it sounded a lot like a stock car on the Interstate. I think with 10:1 compression, overdrive, and fuel injection I could do better.

04-22-2009, 02:59 PM	#1
Ken Haase Member Join Date: Mar 2007 Posts: 233 Likes: 0 Liked 1 Time in 1 Post	mixing early/late BBC parts Is it possible to use MkIV ('86 vintage) heads on a Gen.6 block? I thought I remembered reading that there is a head gasket that would allow this without any fluid leaks. Thanks for any help.

04-22-2009, 06:05 PM	#2
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,116 Likes: 1,573 Liked 1,830 Times in 415 Posts	Re: mixing early/late BBC parts That's an "iffy" situation. FelPro makes a few gaskets, you need to call their tech line or look at a catalog. __________________ Alan Roehrich 212A G/S

04-22-2009, 06:47 PM	#3
Ken Haase Member Join Date: Mar 2007 Posts: 233 Likes: 0 Liked 1 Time in 1 Post	Re: mixing early/late BBC parts Thanks Alan. I was pretty sure you would know and also respond. Ken

04-22-2009, 07:02 PM	#4
Mike Taylor 3601 VIP Member Join Date: Oct 2008 Location: Somerset,Ky Posts: 1,372 Likes: 354 Liked 307 Times in 103 Posts	Re: mixing early/late BBC parts I know it can be done because I seen 502 blocks used to build 540's use aftermarket heads like Alan said call fel pro tech line to get right gasket catalog has that info but is confusing so call them to verify. Mike Taylor3601

04-22-2009, 07:06 PM	#5
Rich Biebel VIP Member Join Date: Jun 2007 Location: Northern New Jersey suburbs Posts: 2,314 Likes: 25 Liked 544 Times in 213 Posts	Re: mixing early/late BBC parts That is definately no problem. I built a 502 for a bracket/street driven car and used a GenVI block with early oval port, closed chamber heads. I can't recall what head gasket I used but I belive it was a GM gasket. That engine is still going. It never had any problem and has run in the 9's after it was transplanted from a street car into a racecar. I got the info for what I needed and bought some parts from one of the GM Performance parts dealers thru their catalog. Pace Chevrolet. Scoggin Dickey is another good source. Lots of good info in those catalogs.......... __________________ Rich Biebel S/C 1479 Stock 147R

04-23-2009, 12:18 PM	#6
Ken Haase Member Join Date: Mar 2007 Posts: 233 Likes: 0 Liked 1 Time in 1 Post	Re: mixing early/late BBC parts Thanks for the help guys. I'm trying to come up with a viable engine for my dually. My grand experiment with Rectangle port heads was a bust, even with revs of 3 grand plus. I should have known better; just gettin' stupider with old age. I now realize why the diesels are the engine of choice. I just can't afford one.

04-23-2009, 05:33 PM	#7
Alan Roehrich Veteran Member Join Date: May 2006 Location: Murfreesboro TN Posts: 5,116 Likes: 1,573 Liked 1,830 Times in 415 Posts	Re: mixing early/late BBC parts Ken, the hot setup is the old closed chamber oval port heads, or the Vortec heads. About 96 to 100cc chamber, and 2.19 intake valves with 1.88 exhaust valves. If you can get 10:1 compression it will work fine. My old 454 had about 9.5:1 and it really wasn't enough, even though I went down in cam to a 218/.520. An all steel flat bed truck, with steel wheels and no overdrive it would get 12-14 loaded or not, and pull 20K pounds with ease. With the air on. Of course, with Camaro headers, 3" pipes, and huge mufflers, it sounded a lot like a stock car on the Interstate. I think with 10:1 compression, overdrive, and fuel injection I could do better. __________________ Alan Roehrich 212A G/S