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**MikeB** · 10-08-2003, 01:34 PM

Yep, 72longbed is right. Over-sized primary header tubes can hurt low speed torque. For a mild 383, 1-5/8" primaries are a good compromise between low speed torque and high speed hp.

From the collector on back, 2-1/2" pipes and mufflers are best. Larger won't hurt torque, but I doubt you'd notice any performance gains.

Heck, my mild 383 has DynoMax Chevelle shorty headers with 1-1/2" primaries, along with 2-1/4" exhausts and DynoMax Super Turbos. It pulls like a freight train off idle and revs to nearly 6000 rpm.

10-08-2003, 01:34 PM	#3
MikeB Senior Member Join Date: Jul 2000 Location: North Texas Posts: 3,665	Yep, 72longbed is right. Over-sized primary header tubes can hurt low speed torque. For a mild 383, 1-5/8" primaries are a good compromise between low speed torque and high speed hp. From the collector on back, 2-1/2" pipes and mufflers are best. Larger won't hurt torque, but I doubt you'd notice any performance gains. Heck, my mild 383 has DynoMax Chevelle shorty headers with 1-1/2" primaries, along with 2-1/4" exhausts and DynoMax Super Turbos. It pulls like a freight train off idle and revs to nearly 6000 rpm. __________________ Mike 1969 C10 LWB -- owned for 36 years. 350/TH350, 3.08 posi, 1st Gen Vintage Air, recent AAW wiring harness, 5-lug conversion, 1985 spindles and brakes. 1982 C10 SWB -- converted from 250-six to roller cam 350, Vortec heads -- sold 1981 C10 Silverado LWB, 305, TH350C -- sold, but wish I still had it! 1969 C10 (not the current one) that I bought in the early 1980s. Paid $1200; sold for $1500 a few years later. Just a hint at the appreciation that was coming. Retired as a factory automation products salesman. Worked part-time over the years for an engine builder and a classic car repair shop. Member here for 24 years! This is the very first car/truck Internet forum I joined. I still used a dial-up modem back then!