outlaw_stck Posted July 12, 2004 Report Share Posted July 12, 2004 If i were to put 1 5/8''primary -3''collector heddman headers on a chevy 305, would i be getting more low end torque or would i lose it? Also, is 1 5/8 to big for a 305? Link to comment Share on other sites More sharing options...
Chuckman77 Posted July 13, 2004 Report Share Posted July 13, 2004 It depends on what type of exhaust you had on before. Link to comment Share on other sites More sharing options...
Truck99 Posted July 13, 2004 Report Share Posted July 13, 2004 Like Chuck said, you would have to tell us what the motor was breathing out of previously before anyone could guess. And even then it would only be an educated guess unless you posted alot of information about the motor. As a general rule, smaller tubes/collector will improve bottom end torque. 1 5/8" primaries might be a good choice if this is on a race motor, but you may want to find some 1 1/2" primary headers if they are for a street motor. cs Link to comment Share on other sites More sharing options...
outlaw_stck Posted July 13, 2004 Author Report Share Posted July 13, 2004 MOTOR Edelbrock EPS performer Intake w/ 500 cfm Edelbrock carb. the rest of the motor is stock. as far as the cam is concerned..im loocking at a couple, but i dont know alot about all that, so if anyone knows about valve train/cams, please let me know. it has ram horn manifolds to dual 12'' glass packs coming out from behind the truck (its a SWB chevy)..the tubing runs from the manifolds about to the back of the cab.(where the glasspacks are) then from there , the tubing runs to the back of the truck. Link to comment Share on other sites More sharing options...
Tim Posted July 13, 2004 Report Share Posted July 13, 2004 This is probably a silly question, but it this your daily driver? I am not sure if you would want to get smaller than 1 5/8" primary, that is pretty much the standard for a street car/truck. Judging by your setup, 1 3/4 is way too big. I would go down to a maximum of 2 1/2 for the rest of the exhaust tubing after the collector. Anything bigger than that and you are going backwards... IMO. Tim Link to comment Share on other sites More sharing options...
thr_spectator Posted July 13, 2004 Report Share Posted July 13, 2004 1 5/8 sounds a little to big for a 305 Link to comment Share on other sites More sharing options...
outlaw_stck Posted July 13, 2004 Author Report Share Posted July 13, 2004 yes, this is my daily driver. Link to comment Share on other sites More sharing options...
Chuckman Posted July 13, 2004 Report Share Posted July 13, 2004 I would go with 1 1/2 headers and 2 1/2 exhuast.jmo Link to comment Share on other sites More sharing options...
Tim Posted July 13, 2004 Report Share Posted July 13, 2004 Here is a pretty good article that will help you choose. I personally don't think you would notice a difference with either the 1 1/2" or 1 5/8" primaries and if it were my car with a lightly modded engine, I would go with 1 5/8"... JMO. Tim Selecting Header Sizes Link to comment Share on other sites More sharing options...
poorboy Posted July 23, 2004 Report Share Posted July 23, 2004 I think I would stay with the ramhorn exhaust manifolds if it is a street vehicle. They flow better than the stock 305 manifolds and if the motor is relatively stock they should work fine. Link to comment Share on other sites More sharing options...
Pacecar Posted July 24, 2004 Report Share Posted July 24, 2004 Suggest you register at this website and use their calculators for sizing headers. http://www.headerdesign.com/login/index.asp Link to comment Share on other sites More sharing options...
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