Got the block prepped to install some newly rebuilt heads and looked at the gasket set I got at NAPA and it says to not install if engine is bored more than .030 (detonation).

OK, so these have to go back because mine is .060. Anyone know of a part number for a head gasket for our engines that has the correct .060 bore?

Thanks!

John

 

Have you checked your wall thicknesses? Max recommended overbore is 0.040" on these engines.

 

The gasket ID should be 4.1 inches. That is +0.100 overbore. I don't think that you can bore these blocks +0.100, but the gasket should work for +0.060. There could be some tolerance issues with the bore center in the NAPA gaskets, but +0.040 is a lot of tolerance.
You should have your cylinder wall thickness checked if you are +0.060.

 

I appreciate all the concern about wall thickness and all. Yes it was checked, yes it is fine. This one allowed for .060. :smile:

But that still does not answer the question; I am still looking for a part number of a gasket that will clear my 4.060 bore.

Cheers!

John

 

Fel-Pro 8347PT-1 is a very common and very good head gasket. it's the only one i've ever used and i have a new set of them going on very soon. as stated in the earlier post the bore diameter for that gasket is 4.1", more than enough for your .060" over. what is the brand/number of the head gaskets that came in your set? the NAPA by me is big on Victor gaskets, i guess they're OK but i really prefer Fel-Pro. BTW, i remember literature from back in the day warning that max overbore is .003"!!! they knew about the core shift as they came off the assy line.

 

I always use FEL-PRO #1013 head gaskets. They are steel core and have a pre-flattened wire ring. They are listed as performance gaskets. They have a bore diameter of 4.1". I have never had a motor bored +0.060".

Here is a number for Federal Mogul, the makers of FEL-PRO. Call and ask them about your concern. They don't list an email address.

World Headquarters
Federal-Mogul Corporation
26555 Northwestern Highway
Southfield, Michigan 48034
U.S.A.

Main Telephone: 248-354-7700


BTW, pre-ignition could occur if the gasket overlaps the cylinder in some location.

Detonation could occur from the increased compression of a +0.060" bore.

I assume that you figured in your total CR in the motor rebuild. If so, then you should have no worries about detonation.

 

i just ran some numbers, i set up a 400 at stock 4" bore(8.17:1) and then plugged in 4.060"(8.37:1). my numbers might not be perfect? but the difference in CR was .2, or two tenths of a point. hardly a major detonation concern where i come from. the difference from 4.030" to 4.060" would be somewhere around half the .2? my first reaction to hearing that they actually warned of detonation in the gasket set was WTF?

 

In case anyone is curious. The block is zero-decked and I had put a set of aussie heads on. Gave me about 11.2:1 Static, DCR unknown. But it ran hard and was on the edge of 93 pump gas. I wanted to lower the compression so I rebuilt the factory 78cc heads which will bring the static down to 9:1 and I should be well withing 91 range.

Thanks everyone for the part numbers. Yes, the NAPA ones are Victor-Reinz gaskets with the little warning paper in there. I'll be there tomorrow ordering the FelPro's as I've alway been partial to them in the past.

Cheers!

John

 

that would change the numbers i used a little then! i re-ran using a zero deck, .045" gasket thickness, and 6cc reliefs? and came up 9.79:1 at 4" bore and 10.05:1 at 4.060" bore. still only .26 difference. what pistons are you using, do you know the relief/dish volume?
http://raceabilene.com/kelly/hotrod/compression.html

 

Yes, they have the 13 cc dish in them.

Cheers!

John

 

9.18:1 at 4" and 9.42:1 at 4.060" for a difference of .24:1. about a 1/4 of a point. i would suspect that the actual CR would be slightly lower. that might run on pump regular if the cam isn't too short and with the advance tailored for it? unless you really don't want the Victors in there i wouldn't sweat the warning at all, unless you know of some other reason? how do the gaskets look around the bore, are they too close to the edge?

 

Would you post the part number of the head gasket and or the gasket set?

For the most part I prefer Victor-Reinz. Felpro does have a lot of great gaskets, but if you consider the whole line, Victor is tough to beat. FelPro does a lot more "marketing" and therefor appears to be "the one"

Victor-Reinz does more OEM gaskets than anyone.

 

The gasket is a NAPA 3502 from Victor-Reinz. Here's a picture of the note inside:

 

That even looks like an older style of gasket to me. I could be wrong but I thought they had a newer style. I will look in my inventory at work on Monday. Your paper, if I interpret it correct, is also about 4 years old. (9/01)