Stock 1979 360 with Speedmaster head question

-
FWIW... the surface finish on the Eddie heads out-of-the-box are plenty fine enough for the MLS gaskets (at least the ones we got). I would not be surprised if the SM's were smooth enough too. I also think Cometic relaxed their RA number a bit in the last year or so; it may have been as simple as changing their maximum RA number to 'recommended'.

MLS head gaskets are getting so common all over in factory engines anymore that getting a shop to do the fine finish is not any issue, from what I have seen in the last few years locally. So it seems like it is wise to finish the deck to around 50RA anyway regardless of the gasket type, unless it costs you an arm and a leg.

I'd be interested to hear if it a significant cost for anyone. My last 4-banger block cost $85 to mill flat and finish to a fine RA, this past January. Square decking a 340 block to a fine RA number was $265 4 years ago.
 
I often long for the days when we pulled old piston rings out of the trash to go on the used piston that came out of a 100,000 mile pickup engine that blew up ten years ago.

Then we would use Permatex on the old head gasket, find the best used rod bearing you could find, bolt it together, and run the local dirt track with the same junkyard dog motor for the next 8 weeks.

My first trip to Bonneville was in '79 and I paid for my place sleeping on the motel floor by washing blown up SBC parts in the motel bathtub. Then watched the junk motor get an A/SR past the 140 mph mark on the salt.

Today's new racers would have new parts air freighted over night and likely never go that fast with new parts.
 
Krooer, you would have liked some of our side-of-the road emergency repairs in rallies. One event, the float in the carb broke off flooding the carb. We were 20-30 miles from the finish, so I just turned the fuel pump on 'til the engine started to choke, then turned it off 'til it started to die.. all while driving a wooded stage road at speed and shifting etc. LOL

Then there was that beaver dam.....
 
lots of threads on quench do a search
you have quench which is two cold surfaces (piston and head) with not enough fuel between to burn/ ping/ detonate
then you have "squish" which forces the gas to jet out into the chamber and have lots of motion which quickens burn
you want the chamber at tdc to be equal distences from the plug for a good flame front
what you do not want is a 440 chamber with the plug way over on one side (or early sbc)
perhaps someone will repost KBs Chief Engineer John Erbs write up on "quench" but he's talking about squish
 
You must log in or register to reply here.
-

Back
Top