360 pistons?

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duster wonder

duster wonder

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tried searching forums and got confused

360, duster, budget build, have to go .030 over, want to run mid grade pump, 9.3 cr?

looking to see what pistons to use all this technical words confuse my brain

http://www.summitracing.com/parts/SLP-H405CP30/

looking at these but dont really need 4 valve reliefs

street use, cold starts and must be hyper

thanks all
 
The 4 valve relief speed-pro's wont get you over 9:1 without some serious cutting. If you want a set I have a set of .040's in the H405cp that you could have cheap. The KB107's are the go-to piston for a lot of guys, but the 2 valve speed pro's H116's are also a good piston.
 
The KB-107's are a bit tall. You could run a way thick gasket to get you to a 9.5-1 IF it sits at zero deck. Often, the slugs sit down the hole. It varies a bit, but the last 2 I did were down 020.

I'd use the KB-107's
 
The H116's are better than the KB107's only for the simple reason that you do not need to file the rings to use them. I like the coated skirts too. J.Rob
 
Both are Hyper-U-tecic and should have the rings properly sized regardless. IMO, there better due to the coated skirts. MP use's them in there create short blocks.
 
rumblefish360 said:
Both are Hyper-U-tecic and should have the rings properly sized regardless. IMO, there better due to the coated skirts. MP use's them in there create short blocks.
Click to expand...

I was referring to the extra time required to file the rings to the KB specific large gap. J.Rob
 
Personally I always like to check the end gap on anything I put together and if you have a ring file it doesn't take much time to set the gap. As for using the KB107's you have to remember they weigh a lot less than factory piston so the assembly will need balanced. The H116's are close to the factory pistons weight so you wouldn't have to balance it, although it's always a good idea since Ma Mopar's balancing wasn't all that great. Either the H116's or the KB107's are higher compression, generally in the high 9's with std. LA heads that haven't been cut much. If you want compression in the lower 9's the H405's are a better choice. Yes you don't need 4 valve relief's like they have but those valve relief's will lower the compression to where you want it.
 
Im running the 405cp pistons and you need a pretty small chamber to get into the 9s they still sit .048 in the hole on my engine. But they put the compression just under 9 to 1 which is where I wanted it. With a stock .030 replacement piston it sat .098 in the hole and my compression figured out to be 7.8 to 1.
 
LOL, yea, that 7.8-1 is a figure I come up with a few times on a few different engine sizes. My B block 400 was the last one. (ECHO - echo - echo )
 
well the h116 are too much compression.. and im going .030 over now.

heres the chart i have ben looking at, and the summit calculater confirms, h116 is a little too much but the 4 reliefs are a little too low, which a thinner head gasket can fix, called indy heads said my heads were 64-65 ccs the 405's are also half the cost

http://www.campbellenterprises.com/mopar_speed_pro_trw_forged_pistons.htm
 
RAMM said:
Wrong--The H116cp's are hyper-e and use conventional ring gaps. The KB 107's require about .010" more than conventional. J.Rob
Click to expand...

Thanks........
What is Hyper "E" ?
So far, the only difference I have noted between the 2 makers of the slugs are the amount of silicone content there made with. Difference in slugs construction that is.
 
Ahhhhh. Slang... :thumblef:

Besides the silicone content, what is different about the content of the slugs and why is one required to have more ring gap?

The contents of the casting is all I can think of.
 
rumblefish360 said:
Thanks........
What is Hyper "E" ?
So far, the only difference I have noted between the 2 makers of the slugs are the amount of silicone content there made with. Difference in slugs construction that is.
Click to expand...

Rob the reason you have to gap the top ring wider on the KB's is they moved the top ring farther up on the piston exposing it to more heat so the gap closes up more when hot. I saw one come out of an engine that the guy didn't gap them wider and it wasn't pretty. Snapped the top of the piston right below the top ring.
 
duster wonder said:
well the h116 are too much compression.. and im going .030 over now.

heres the chart i have ben looking at, and the summit calculater confirms, h116 is a little too much but the 4 reliefs are a little too low, which a thinner head gasket can fix, called indy heads said my heads were 64-65 ccs the 405's are also half the cost

http://www.campbellenterprises.com/mopar_speed_pro_trw_forged_pistons.htm
Click to expand...

Playing with gasket thickness does work to get the compression in the ballpark but one thing you have to make sure of when running a thin gasket is that the heads and block are really really flat. A few yrs. back I tried running the Mopar thin gaskets (.028" thick) and I checked my block and it was within .0015" of being flat end to end & side to side. The heads were freshly milled so they were spot on. Lasted about 200 miles and a gasket started leaking. I didn't want to yank it all apart so I put a set of Fel-Pro's (.040 thick) on it and it sealed fine and I couldn't tell any diff. in performance although I didn't dyno it. I know guys that have gotten lucky and not had problems with the thin gaskets without decking the block but it's always a gamble IMHO. Having the block decked is a couple hundred bucks but it's well worth it if you don't like pulling the heads on a fresh engine to change the gaskets. Square decking the block is even better as by the name insinuates it means they equalize the decks side to side and front to back, thus it is square. Standard decking doesn't do that. Just flattens things, which is fine to get things to seal up but looses a little on the performance end. I totally understand a budget but don't go cheap on the machine work. The lower cost pistons are just fine though.

BTW: what heads do you have? I assume their new since you said Indy says their 64-65 cc's.
 
fishy68 said:
Rob the reason you have to gap the top ring wider on the KB's is they moved the top ring farther up on the piston exposing it to more heat so the gap closes up more when hot.
Click to expand...

AAAAA-HA! Thanks!
 
duster wonder said:
well the h116 are too much compression.. and im going .030 over now.

heres the chart i have ben looking at, and the summit calculater confirms, h116 is a little too much but the 4 reliefs are a little too low, which a thinner head gasket can fix, called indy heads said my heads were 64-65 ccs the 405's are also half the cost

http://www.campbellenterprises.com/mopar_speed_pro_trw_forged_pistons.htm
Click to expand...


What heads are you running? If they are a closed chamber head. I would look for a piston that gets you close to 0 deck, so you can take advantage of the quench. Otherwise if the if the 405 works for you i would get them here.
http://www.ebay.com/itm/Dodge-Chrys...Parts_Accessories&hash=item27c4c57445&vxp=mtr
 
well i wish they were new.. haha no the 308 casting and closed chamber...

i think closed chamber anyhow i seem to not remember much tonight

reason i said indy guy is because i called to find cc"s and the only heads that are better are their 1200 buck aluminum heads.. go figure

also, the kit that the machining guy is offering has the 405 pistons ssssoooooooo
 
If your going with the kit and settling on the 405 pistons because that is what he has and you do not have enuff money to get what you want, or need, I suggest you sit back and re-think your position and bank roll some money. Your not ready to do this yet.
 
rumblefish360 said:
AAAAA-HA! Thanks!
Click to expand...

welcome bud.

rumblefish360 said:
If your going with the kit and settling on the 405 pistons because that is what he has and you do not have enuff money to get what you want, or need, I suggest you sit back and re-think your position and bank roll some money. Your not ready to do this yet.
Click to expand...

Good suggestion.
 
duster wonder said:
well i wish they were new.. haha no the 308 casting and closed chamber...

i think closed chamber anyhow i seem to not remember much tonight

reason i said indy guy is because i called to find cc"s and the only heads that are better are their 1200 buck aluminum heads.. go figure

also, the kit that the machining guy is offering has the 405 pistons ssssoooooooo
Click to expand...

Someone correct me if I'm wrong but I believe 308's are open chambered. Most open chambered heads run 70 cc's or more unless they've been milled quite a bit.
 
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