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Having trouble finding FELPRO 20 over head gasket

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SnowBird

15+ Year Contributor
527
0
Jul 9, 2006
Cleveland, Ohio/Tampa, Florida
I usually order felpro gaskets off of advance auto, but they dont list any for 20 over blocks. This is what I need seeing my block is 20 over right? for some reason I thought the stock ones had a little space on them still.
 
I wouldn't use a fel-pro head gasket on your car. They are not known to hold up to boost very well. Just get a cometic mls gasket for it and be done with it.
 
get a cometic mls gasket for it and be done with it.
If he only knew what tolerances those MLS gaskets will take. Your head and block have to be near perfectly straight, or it won't seal. This requires a complete engine disassembly, taking the head/block to a machine shop and having them machine it to a true flatness. The only advantage I see in this is if he's doing a complete rebuild. I would just run a Mitsu HG and be done with it.
 
If he only knew what tolerances those MLS gaskets will take. Your head and block have to be near perfectly straight, or it won't seal. This requires a complete engine disassembly, taking the head/block to a machine shop and having them machine it to a true flatness. The only advantage I see in this is if he's doing a complete rebuild. I would just run a Mitsu HG and be done with it.

Correct. Not only is the MLS gasket more expensive, but the effort, time and money spent will make you wish you didn't go this route, unless you're pushing some serious numbers.
 
Plus, the stock HG is proven to hold over 20psi without leaking. However, most people running them will install ARP studs to prevent the head from lifting due to increased cylinder pressures. And as cheap as they are, how can you go wrong?
 
The combustion seal on the mitsu hg is 3.405 in Diameter, which is .060 thou over factory bore. So you can run the factory hg on a .020 over bore with no problems :thumb:
 
I say go with OEM HG with the ARP head bolts and you should be fine if your not planning to run more than 20-22psi of boost. Alot of people think the gasket keeps it from blowing out but its the studs that is the key here. Keep the head tucked against the block and the HG will do its part.

If your looking to run high boost levels or down the road go with a multilayer gasket and ARP's. I have a Cosmetic HG and I have no issues plus a o-ring head helps with that also. FFWD Connection sells some awsome HG also:

FFWD Connection

One other thing I recommend is after running your car couple hundred miles go in and re-torque the head and you than should be safe than on out.

If anyone knows different please correct me on this...
 
Since there seems to be alot of talk about OEM Mitsu HGs which are you guys talking about.. The felt one? Or the MLS one? I plan on running the MLS one but don't really want to have my head machined.. is this okay if its the OEM MLS one (From SBR)? Also when you guys bring your heads to a machine shop, are they dissambled?
 
Since there seems to be alot of talk about OEM Mitsu HGs which are you guys talking about.. The felt one? Or the MLS one? I plan on running the MLS one but don't really want to have my head machined.. is this okay if its the OEM MLS one (From SBR)? Also when you guys bring your heads to a machine shop, are they dissambled?

This head gasket
As for bringing the head to the shop, I always disassemble mine, and throw each valve component in a marked ziploc bag(total of 16 bags, 1 valve, spring, clip, and guide in each bag), as the machine shop charges an extra $65/hr to disassemble the head. I've only done this once, since I have full access to a machine shop on the weekends(FREE). So its up to you, if you want to pay more money and let them do it, thats fine if you don't feel comfortable doing it yourself.
 
Correct..normally, factory bore headgaskets in reality are good for .40 over like cometics and OEM mitsu metals, any more than that you need to have a specific overbore gasket.



Joe
SBR

I hate to point this out but being a vendor you should realize that .40 is almost 1/2 an inch. It should be .040. :thumb:
 
This head gasket
As for bringing the head to the shop, I always disassemble mine, and throw each valve component in a marked ziploc bag(total of 16 bags, 1 valve, spring, clip, and guide in each bag), as the machine shop charges an extra $65/hr to disassemble the head. I've only done this once, since I have full access to a machine shop on the weekends(FREE). So its up to you, if you want to pay more money and let them do it, thats fine if you don't feel comfortable doing it yourself.

Okay cool thats the head gasket I was looking at. I am more then capable and comfortable just don't have a spring compresser or good work area at my house thats all. Also only have expierence on honda heads.
 
My composite "fail-pro" looks 100% like the composite mitsu stamped hg I replaced (before I put it on). I popped the mitsu HG at 30 psi and a poor tune (all me:D !). I've been running the "fail-pro" for thousands of miles at said boost. I run ARP head studs. I believe this makes the difference. I have never tested a "fail-pro" w/ stock head bolts. I HAVE popped a new composite mitsu head gasket w/ stock 6-bolt (thicker than 7-bolt) head bolts. Thus, I believe if you're running enough horsepower (not boost btw) to pop a "fail-pro" then you you really should stud the head. Considering the cost of either head gasket and the time involved, it's cheap insurance.

I'm not saying that stock composite mitsu gaskets are inferior to Fel-Pro. I'm jsut saying that head studs are worth the investment. 20 thousanths does fine on a local's "standard bore" fel-pro.
 
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