Ok, I have the Thorleys and yes I realize the 1 5/8s primaries will not be as efficient as larger ones. My question is should I buy 1 3/4s now or wait a little while and run the Thorleys with 10psi until I can get the 1 7/8s? How much is it going to hurt me running the Thorleys?


BTW mods will be: 216/224 .551, Stg1 706 heads (p&p with larger ls1 valves), and MP 112.

 

Have you read about the TSP f body 1 7/8s headers? They were around 500 last time I checked and they fit our trucks.

 

Go with the 1 7/8 gives better flow and if u have full exhaust xpipe ,u would see more hp gains, what u have now wont hurt anything just restrict ur hp gains.i had ps 1 3/4 high flow cats x pipe and true duel 10 series fm exhaust 6.0 mp112 2.75 pulley and the truck was a screaming t-Rex

 

The ones you have now will work fine.

 

TSP headers seem like a hella deal, thanks for the heads up.

Mine will have the 2.8 pulley.

I guess my real question was the HP-cost difference worth it?

 

Personally I dont think the cost vs. HP gain is worth it. If you didnt have headers already then ya I would go with the larger ones but seeing you already have some.... Blown setups are not as picky with the exhaust as a NA setup. Your limiting factor is going to be the blower.

 

OK, well I appreciate the info and saving me money!

 

If its gonna be a dd street machine then i would deff stick with the thorly's, the 1 5/8" primarys would deff help your torque down low to get it rolling off the line..