So I pulled the trigger on a ls7 shortblock with forged diamond ultra lite pistons arp rod and main bolts . Think it’s at 11.5 compression with my heads being .030 milled. What gap
should I go on the pistons for boost/nos/NA? Is there a ideal safe gap for all?

On my boosted forged 427 build I’m running .024 top and second ring. Also running lower compression 9.5:1.

How much nitrous are you going to spray?

we ended up doing .27

11.5 I don’t think is to much for boost on e85 flex fuel I had it setup for either most likely do nitrous a 150 shot

with this shortblock maximum 175 just to hit the 800whp mark if I make 625NA on e85

engine builder is some older retired feller who had like three back and knee surgery’s and works out of home now. Was super skeptical and hesitant but as the pictures came I believed more and more this guy has
a incredible garage with like 5 ls7s all Done up short or long blocks with 4-5 sets of heads. He told me the weakest part is the connecting rods. And how much of a difference will lighter pistons make only by like 6 grams each I think

i want 250 honestly but the block won’t handle it 175 for now is Fine. I heard it’s all in the tune to make these engines last......

yes standalone also

I would do a smaller shot since it seems that block is not sleeved and has stock crank/rods. Correct? Compression is too high for boost even on e85. It can be done but reliably I don’t think so.

I’m running E85 on my build also with ductile iron sleeves. Not trying to end up ruining this motor with detonation like I did on my stock block

Yeah that’s a pretty accurate statement for the tune. If you pick parts appropriate for your intended level of abuse and assemble them correctly there is no reason it won’t last a reasonable amount of time assuming it’s tuned right. Of course there are a million variables here so it’s always a crap shoot. Will a stock block handle a 250? Sure but a “reasonable lifespan” is different for each person. Some people want to build stuff cheap, put 40 pounds of nitrous through it a week and have it last 100K miles lol.
I would have done .024” on the top ring(no boost). Too much is way better than too little when it comes to end gaps.

**** it I guess I’ll do a little 150 shot or boost down the road but at 11.5 can I add a thicker gasket. I’m gonna try to hit. My 600whp again with 2 inch headers Mamo msd nw102 haltech my AHP heads and a custom ground cam. Also do a fuel system and e85 at the same time flex fuel.


i mean for 5400$ shipped shortblock with stock
block crank and rods with diamond pistons and arp
stuff I couldn’t find anything cheaper pre built

**** me man I mean these stock ls7 sleeves should be good for 150 shot on e85 and c16 but I don’t want to
go through this again. I might just sell my short block again smh. But if I can get high miles NA at 600whp I’ll just stay NA and down the road I guess a year or two sell the shortblock and build something crazy a TT 427