kgkern01

iTrader: (10)

I'm ordering my parts for my 13.5+ cr 383/388 build and I have a few questions before ordering parts. I am debating whether or not I would need MLS gaskets for that much compression or if the .026 Mr.Gasket would be ok. I am aiming for around .030 quench as well.

Wicked94Z

iTrader: (26)

I've had great luck with Mr Gasket MLS headgaskets, but I think they're .039 ot .040. Have you ordered pistons and rods yet? Block machined yet? Just hang the piston out.

kgkern01

iTrader: (10)

I have 6" rods, have a stock (unmachined) 4-bolt block, was going to order crank and rods today. I was thinking of 1 of 2 options.

1) 3.80" stroke with 1.125 piston, deck .015 (assuming standard .025 currently), leaving .030 quench with a .040" gasket.
2) 3.75" stroke 1.125" piston, deck to 9.005 with .026" gasket leaving .031 quench.

Block will be machined and shortblock assembled by the shop.

Puck

iTrader: (17)

Cometic will make you pretty much any gasket you want at any thickness and for any compression.

They are pricey though!

kgkern01

iTrader: (10)

Yeah custom gaskets are expensive, but if I can use the .040 gasket with .005-010 "out of the hole" to get good quench that may be the route to go to save some $ while still "doing it right".

great421

iTrader: (1)

I regularly push 12 lbs of boost into my 383 using Mr. Gasket MLS head gaskets; at the stock C/R too, so they'll hold 13.5 to 1 just fine!

: )

quik95lt1

iTrader: (7)

cometic ftmfw....i ran a non mls gasket at 13.2:1......it doesn't end well lol......i run cometics now at 14.5:1 with no issues at all......as for quench unless you got some strong *** steel rods and a perfect tune do NOT go under .030 quench

kgkern01

iTrader: (10)

Yeah after doing a little more online 'research' I've decided on a .35-.40 quench, I don't think the risk is worth the rewards there.

Side question, what about a tiny flat dome (.10 or less) to get an extra point compression vs staying flat-top and 13.5 cr?

quik95lt1

iTrader: (7)

what about it? lol if ur asking if its ok yes domes are fine just be prepared to run good fuel

Ed Wright

iTrader: (1)

I never had a GM B body LT1 head gasket fail with 14.25-1. Good fuel and tuned correctly. I would not try to run less than .033" with steel rods. Closer and you will likely touch the pistons to the heads which upsets ring seal at TDC. That cost power. Lots of power with good ring seal. Hit the heads hard can pinch rings. .035" is safe and will make the same power as .032" or .033".

kgkern01

iTrader: (10)

Yeah it's a strictly E85 build, which is why I'm trying to maximize compression to get the most out of it. That's why I was asking if it was worth it to go with small flat dome pistons for ~14.5 vs flat top for 13.5 on E85, as I have heard that flat tops produce a better flame?

1961ba427

iTrader: (26)

I don't think a small dome like you are talking about will hurt flame travel that much. You could always clearance the dome some in the plug area if you're really worried about it.

Ed Wright

iTrader: (1)

It amazes me how many are willing to run that nasty, corrosive crap through their engines.

kgkern01

iTrader: (10)

I've been running it for 6 years in my heads/cam car. It's approx 105 octane, resistant to detonation, and keeps the fuel system clean. I have no signs of corrosion in my fuel system from it. I know a few others here are having good results with it...