Dipstick

I'm putting a 99 LS1 in a sandrail and was wondering if I could cap off the "Vapor Vent Pipe" line to the TB. The FSM refers to this as a vapor discharge line to rid the engine of air. Will this cause any problems or is there another way for the air to get out of the engine? I will be using a Ron Davis radiator which I doubt has a provision for the vent line. Could I terminate the line in an over-flow bottle if it was sealed?

I will be running 1 or 2 large K&N air filters and the exhaust will be stock manifolds going to 18" bullet mufflers. Each side will be about 36-48 inches long. How much HP will this otherwise stock 99 be putting out.

WILWAXU

iTrader: (6)

Figure the 99 LS1's dyno at least 280 to the wheels.. so probably in the 320hp range at the flywheel.

Not sure on the vapor vent. Moving this to the conversion section... one of those would probably know.

Speartech

iTrader: (14)

No, don't cap it and don't send it to a sealed overflow bottle (that would be the same as capping it). That line needs to always be able to flow water. You need to add a nipple to the radiator on the return side, or to the return hose with a tee, or to an added fitting on the return side of the water pump. There are several choices, but you should implement one of them.

Dipstick

Thanks. I've already drilled and tapped a 1/8" pipe thread hole for an Autometer water temperature gauge sensor on the top of where the water inlet hose goes. I can use that for the return hose from the vent pipe and put the water temp sensor in the right rear head. I've already re-tapped it for a reducer to 1/8" pipe.