BB w 915 closed chamber heads. The dished pistons I have in mind have the perfect deck height which would give me good quench (.035") but the problem is that the diameter of the perimeter around the dish is .445" wide as opposed to a much larger quench area on a legitimate set of quench pad pistons. I can get these very cheap but if this will not be enough FLAT AREA to give me effective quench even though the piston to head distance is correct(.035") then I need to move on. What do you guys think? Thank you for your time.
Posted By: Get-X
Re: quench Q's - 12/23/08 05:26 PM
I too am looking for a good set of shelf pistons that optimize quench with 915s. Just a pump gas street motor with a moderate hyd. cam. Trying to run as much compression with pump gas and iron closed chamber heads as possible.
Posted By: GomangoCuda
Re: quench Q's - 12/23/08 05:40 PM
You want a reverse dome piston. Only the area under the combustion chamber should be dished. the other side should be flat with no dish to maintain quench. Keep looking, they're out there.
Posted By: RapidRobert
Re: quench Q's - 12/23/08 05:42 PM
with good quench we could run a CR in the mid 10's on pump gas, no way that high without it. This fantasy buildup is a 440 block, 4.250" 440 source crank, 7.1" chevy rods & some eGay 403 olds cast pistons for just over $100. Problem is the non machined ring around the dish is only .445 wide but with a CH of 1.595, bore of 4.351"(std) it'd work ex for the not enough quench area. Might have to just spend the extra & get it right.
Posted By: RapidRobert
Re: quench Q's - 12/23/08 07:43 PM
alright you guys' expertise has persuaded me to do the right thing here, that & I just think I'd be uncomfortable with a GM part in there, heck I had a hard enough time using an aftermarket HEI module & only then because it was given to me. Thanks guys for taking your valuable time to guide me with this.
Posted By: RapidRobert
Re: quench Q's - 12/23/08 07:54 PM
I used one of those custom brackets that tucks the hei up under the dist, was a noticeable improvement making the ecu/ballast/& wiring dissappear.
Posted By: 1_WILD_RT
Re: quench Q's - 12/23/08 08:00 PM
Back around 97-98 I put a Holley Projection unit on my Challenger, As part of the conversion to use the built in timing with knock sensor it needed a GM ingnition so I locked out a Chrysler electronic & fed the output to a HEI module...The ignition was about the only thing on that whole conversion that was trouble free..I fought that POS for about a year till I went back to a nice reliable carb.... Ford, Chevy whatever as long as it works better I use it...
Posted By: boscosis
Re: quench Q's - 12/23/08 08:53 PM
I installed a 900 CFM Holley Pro-Jection back in 1993. This was no small amount of money for me at the time ($950) and still wouldn't be. It worked OK and I liked and drove the truck with it for about 2 years. When I acquired a different truck I parked the one with the Holley Pro-Jection and only started it up every once in a while. About a year after that the CPU died and would no longer fire the injectors. I talked to Holley and they said the unit was disposable and could not be rebuilt. The only thing thing that they could do was sell me a new CPU for $400.
Needless to say I removed it and installed a carb. After that I would never purchase any Holley FI equipment and I try very hard to not purchase from Holley or any subsidiaries, but as you can imagine sometimes that's difficult with as many companies as they own.
To be fair, my brother has been running the same system trouble free for about 11 years, but I don't want any part of it.
