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85.5mm Headgasket

503oneG

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
Hello All, Im currently assembling my short block. I have JE pistons and Bridgeway H-beam rods. the block has been bored .20 to 85.5mm. My questions is, What head gasket should i run? ive read through a lot of posts, a lot say basic fel pro gaskets work great. being 85.5mm i cannot find that gasket. Im seeing a lot of cometic MLS gaskets. My deck was not resurfaced nor was my head. I removed a MLS head gasket from the knocking short block and it didnt appear to have been leaking. (Re using block and pistons with new H beams and new crank). Should i go for the MLS? power goals 450-475. Thanks, Seth
 

ThunderChild

Supporting VIP
3,762
1,121
Jan 5, 2012
Rathdrum, Idaho
Iirc, the stock gasket accommodates up to 86.5, possibly 87mm bore.

I've loosely been researching gaskets for a 2.4 build, and I recall reading that somewhere.

Either way, a felpro gasket should work for a .020 overbore, these engines aren't like a SBC/SBF etc., they don't need a specific gasket for a specific bore, just 2.0 or 2.4l unless you're way overbored.
 

MattHDSM

Proven Member
86
46
Oct 20, 2018
Ottawa, ON_Canada
My block is .020 overbore (85.5mm) and I'm using a felpro composite headgasket. No issues with fitment for me, but I honestly don't know if a bore matched gasket would matter at that power level. It wouldn't be too wild to think that with crazy high cylinder pressures or when using o-rings, that you might need to take bore size into account, but hey I'm probably making 300hp max so take that with a grain of salt LOL
 

503oneG

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
It made 425 on the stock rods but the topline oil pump failed and took out a rod bearing. Rebuilding the block and adding Bridgeway rods I got a smoking deal on. I’d like another 25whp LOL
 

503oneG

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
Thanks guys for the input. I’ve always been a fan of fel pro gaskets. I’ll go with one of those, now do I go composite or mls LOL
 

jed344

Supporting VIP
1,146
241
Jan 10, 2008
Waterville, Iowa
OEM or felpro composite is all you will need with regular set of ARP's. We have used this set up to mid 500hp and low 30s for boost. I hate MLS gaskets. I run OEM composite with L19's and a O ringed head and it has seen over 40psi without issue.
 

503oneG

Proven Member
30
11
Sep 25, 2020
Beaverton, Oregon
Went with the composite felpro. I have basic arps already
 
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