How much horsepower would I gain with a ported LT1 Intake. Its been ported for a 58mm Throttle body. Would It be worth the 200$ Thanks in advance. Mods in signature.

 

As far as I know, he just opened it up in the front part to fit the 58mm...get some more clarification from him to see if he actually had the manifold ported, not just for the throttle body...

 

He just had it ported for the Throttlebody.

 

i would say not much... 10 at the absolute most and that is with the 58mm tb. now if it were the ports that is a different story.

 

Not worth it for $200 that is for sure. Unless of course it has ported runners etc. which I doubt. Get a dremel and port it yourself and if you don't have a 58mm to match the port it won't help performance at all. Since by your sig you already have a 52mm you are probably at the best it is going to get so save your money and get a cam. Much better investment. Messing with the intake won't gain you much at all especially if you don't have the heads to match it. The stock manifold already outflows the stock heads. I don't think you will see any gain going to a 58mm.

 

With your mods a 58mm is a waste of time. Spend your money on a cam...