And externals need to be mounted below the tank to gravity feed. The pumps are pushers not suckers

Lowered the fuel pump got it to run for a sec then back fires think the valves are maybe too tight

Should have the mods change subject just to avoid any wirdness for psi conversion s

Jay, did you have the engine apart? Maybe a cam change? I've seen many people put too much preload on the lifters of a SBC, and it will back fire and not run every time, but I'm not sure it's possible to accomplish this with an LS platform, to that extent...having said that...you said earlier in the thread that you weren't getting spark. Can you verify spark and fuel?

Ls3 rockers are not adjustable. If a cam swap was done then measuring pushrod for proper length would be the prudent thing to do.

These are hydraulic rollers so unless they are way off it would not keep the motor from running

I'm trying

may just have to roll down to Cali

Ya that's true. Cam was never taken out. It's a crate engine with the 480 cam

I'll get back on it tomorrow.
Thanks for all the helpful hints

Car starts up found out why the car backfires. The rockers were off the valves all he way on a few cylinders.

Think we got it figured out

Dang, Hecho en where?

Two rocker arms have bad bearing so in going to buy a new set and replace them all.

Anyone run roller rockers? Or should I stay with the stock style rocker arms with the Trunion kit?