Thread: 1970's Block & Gen5 Heads?

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Hey now everybody.
This is my first post and I am honored to be here.

I have a buddy willing to let a set of Gen5 heads go for pretty cheap. I am in need of a set of heads real bad, as I torched one side a few weeks ago.
I would be going from a closed 101cc chamber to an open 118cc chamber, thus bringing my compression way down... which is okay with me.

Problem is I am being told that my 1970's era block will not acccept a set of Gen5 heads. Something about the gaskets. I could be wrong, but the last time I shopped for head gaskets I don't remeber them being that block/head specific.

My question (if I haven't been cryptic enough) is; Can the Gen5 heads be run on my old block?

Fel Pro makes the gasket you need. See their performance catalog and look for the head gasket that allows use of Gen V/Gen VI heads on mark 4 blocks.

Good luck

Thanks for the quick response Geezer.

What year did the Mark4 block begin casting? For some reason I thought I was older than that. I don't have the casting number off hand.

I am looking all over the Federal-Mogul web site and I can't find enough information on these gaskets. Any suggestions?

i have done it the f1047 up to 4.540 bore or f1037 for smaller bore the mark 4 block was started in 1965 as the 396 and was end around the late 80s this block has a closed down deck less holes in the deck making for a stronger and better block i think. the 5/6 blocks have a open up deck bigger holes for coolant and re work flow on the deck 5/6 heads can fit on older blocks but not that great of a head less you have put the 7/16 studs on them so you can run the old type ajustable rocker arms you can not run the old mark 4 heads on the gm 5/6 mark blocks there not much around the deck on the older head to hold the head gasket seal were it gets thin is the lifter valley side of the deck

Mark 4 blocks run 1965 to 1991 ish In 91 the Gen V was fazed in.

Originally Posted by pat mccarthy

i have done it the f1047 up to 4.540 bore or f1037 for smaller bore the mark 4 block was started in 1965 as the 396 and was end around the late 80s this block has a closed down deck less holes in the deck making for a stronger and better block i think. the 5/6 blocks have a open up deck bigger holes for coolant and re work flow on the deck 5/6 heads can fit on older blocks but not that great of a head less you have put the 7/16 studs on them so you can run the old type ajustable rocker arms you can not run the old mark 4 heads on the gm 5/6 mark blocks there not much around the deck on the older head to hold the head gasket seal were it gets thin is the lifter valley side of the deck

Thanks.
Okay, so I know I have a Mark4 block.
I get that I can run the Gen5 heads; 7/16" studs recommended and not a problem.

I still need, and can't find, anything on the proper gaskets to use.

Didn't follow with the f1037 and f1047?

Originally Posted by Constant840

Thanks.
Okay, so I know I have a Mark4 block.
I get that I can run the Gen5 heads; 7/16" studs recommended and not a problem.

I still need, and can't find, anything on the proper gaskets to use.

Didn't follow with the f1037 and f1047?

they are felpro numbers the f1037 is a mark v454 gasket . the f1047 is big bore v 502 . alot of the felpro are print out for both water ports older mark 4 and 5/6 the 1037 is the one i have used on the older block with 5/6 heads if mark 5 /6 heads i drill and tap them out for the older 7/16 top and bottom rocker stud ARP makes a stud that works in the mark 5/6 head thats 7/16 and 3/8 bottom but alot of builds i do i used the 7/16 top and bottom stud keeps them from busting off