What are you guys using for performance applications? I currently use the FelPro 10171 because of my current engine bore size. My new block will be a 4.28 bore. What head gasket do you guys recommend for that? I only see one in the felpro catalog for that bore size and it is the FPP-1037. 4.37" x .039" compressed.

Thanks!

What heads? AFR's & other CNC'd heads need the 1017

1037 but you need to drill three holes in the block if they aren't there on the early blocks.

Oops, sorry, it is a Mark IV block, like 1972.
Standard 063 or 215 GM iron ovals

1037's & you will probably need to drill the three holes, two 1/2" & one 5/8".
Very simple & the instructions should come with the gaskets ;)

Thanks Mike. Drill the gasket I hope you mean.
What if I decide I need bit thinner of a gasket, like .030 compressed? Is Cometic my only source for that?
I'm shooting for about 10:1 static CR. With the heads I have, pistons I am looking at....I get 9.75:1 with the piston .005" down the hole.

Mr gasket or GM .022 compress bore size 4.370.Steel shim Gaskets if need part numbers let me know

No actually you need to drill the deck surface of the block and it makes a big cooling difference.

Be sure that the gasket bore is compatible with the head chamber. I was going to use a 4.370 bore gasket but it wouldn't work with my heads.

Ken,
What heads did these 1037's not work with? Your Canfields or stock GM?

Mike, If felpro lists the 1037 for 1965-1990 Mark IV, why would I have to drill the block? What about the coolant holes in the heads? They line up with my block now. I am confused now. What performance felpro gasket do people use for their .030 and .060 over BBC's with GM heads?? :confused:

Originally posted by Epistuff:
Ken,
What heads did these 1037's not work with? Your Canfields or stock GM?

Mike, If felpro lists the 1037 for 1965-1990 Mark IV, why would I have to drill the block? What about the coolant holes in the heads? They line up with my block now. I am confused now. What performance felpro gasket do people use for their .030 and .060 over BBC's with GM heads?? :confused: Jim, yes that was with the Canfield heads. I use the FelPro 10171 gasket. Are you trying to tighten up the quench? What's the reason you don't want to use the larger bore gasket? If you zero deck the block you will have a good quench with that gasket smile.gif

Originally posted by Epistuff:
Ken,
What heads did these 1037's not work with? Your Canfields or stock GM?

Mike, If felpro lists the 1037 for 1965-1990 Mark IV, why would I have to drill the block? What about the coolant holes in the heads? They line up with my block now. I am confused now. What performance felpro gasket do people use for their .030 and .060 over BBC's with GM heads?? :confused: I use the 1037 gasket Jim. It uses a revised cooling pattern which is why you need to drill the three deck holes if you block doesn't have them...no real big deal drilling even after the block is decked....just gotta be careful and debur/chamfer the drilled hole edges. I think those gaskets payed a part in my lil rat staying pretty cool even on street drives with a filled block...more even distribution of coolant.

My engine builder likes the 1017 gasket, even on "small bore" 454 & 427 bbc's. I didn;t like the large 4.500" bore gasket as I felt I was giving up precious compression.

I wonder if Ken's combustion chambers were profiled for a 4.500" bore and the edges of the chamber were too wide for the smaller 4.370" 1037 gasket bore?

Originally posted by 10secBu:


I wonder if Ken's combustion chambers were profiled for a 4.500" bore and the edges of the chamber were too wide for the smaller 4.370" 1037 gasket bore? Todd,

That's exactly the case. I talked with John over at Canfield and he said when Joe Patel designed the heads he delibertly designed a wide chamber smile.gif Having just torn my engine apart for the rebuild I can tell you that even a .051 quench has the combustion area looking good. The only carbon on the piston is on the dome, all the flat surfaces are as clean as a new piston (well, almost). Having said that, I'm zero decking my block to get the quench to .041 with a 10171 gasket. Hate to leave any performance on the table ;)

Ken, Todd,
Here is the deal. I am in the process of building a new motor. I was shooting for 10:1 static CR. My rods are 6.385, my piston (BRC)is 1.395 and if my deck ends up at 9.785, that leaves my piston .005 down the hole. With the 10171, my CR would be 9.72:1. With the 1037 gasket, it would be 9.83:1. I didn't want to go zero deck in case I had some issue down the road and needed to deck the block again?? Maybe I am worrying about it too much and should just stick with the gasket I know works and that is the 10171, it is just that it was designed for a bigger bore than what I will have. If I do zero deck the block (9.78"), I would have 9.82CR with the 10171 and 9.93CR with the 1037.
Todd, I can't find any info on the 1017. Where did you find that one?

What do you think?

Jim,
There is no 10171, it is a 1017-1 & as I posted in my first post & Ken posted you have to use it with most of the CNC chamber heads or the fire ring will hang into the chamber.
Drilling the holes is not a big deal, you can even do it with the pistons in the bores if you cover & tape them off.
The difference between 9.78 & 9.8 is just not worth worrying about,, use the 1017 if you don't want to drill the holes ;)

OK, gotcha graemlins/thumbsup.gif

Thanks guys

Oh,....what do you think about leaving the deck at 9.785? Is that OK, or should I just go zero deck to begin with?

Originally posted by Epistuff:
Ken, Todd,
Here is the deal. I am in the process of building a new motor. I was shooting for 10:1 static CR. My rods are 6.385, my piston (BRC)is 1.395 and if my deck ends up at 9.785, that leaves my piston .005 down the hole. With the 10171, my CR would be 9.72:1. With the 1037 gasket, it would be 9.83:1. I didn't want to go zero deck in case I had some issue down the road and needed to deck the block again?? Maybe I am worrying about it too much and should just stick with the gasket I know works and that is the 10171, it is just that it was designed for a bigger bore than what I will have. If I do zero deck the block (9.78"), I would have 9.82CR with the 10171 and 9.93CR with the 1037.
Todd, I can't find any info on the 1017. Where did you find that one?

What do you think? Jim,

No problem zero decking the block? You can under cut the block again later if necessary, say .010, and just use a taller headgasket and be right back where you started graemlins/thumbsup.gif

Wow, you guys are quick!
OK, zero it is.

Thanks again.

I have a question about this post. I will be boring out a big block shortly. Can normal head gaskets not be used on say .30 or .60 over? I never really thought about this before.

Phil, your basic gasket for BBC is 4.37" diameter. A .060 over 454 bore is 4.31, so you still have room, just be sure it is OK for the heads. Stock GM heads should have no problem. The next size up "off the shelf" gasket appears to be 4.54" bore. That is the one I use now, because my block is .125" overbore.

.125 over, is that on a stock block? :eek: Some people are scared to even go .60 over, they tell me not to.. blah blah your block will be maxed out. Im still not sure, would there be a huge difference in performance or driveability between .30 and .60 over?

Yes the .125" overbore is on a stock GM block. It is a "512" casting from 1972. I built the bottom end of this thing back in 1988 and have been driving it hard ever since. No problems with the block at all. But now the motor is getting a bit tired, bearings are worn, oil pressure is dropping...I know this block can't go anymore, that is why I am starting over from scratch again with a .030" over 454. As far as performance goes, no there is no significant performance increase by going to a 468 over a 460 BBC. You will never feel those 8 cubes.

It will likely run 8 degrees warmer though! Do notice that having just gone .060 over. (Schooch more cylinder pressure as well though)