What size headers for a T Rex cam
Thread Starter
Joined: Aug 2006
Posts: 731
Likes: 10
From: Albuquerque, NM
What size headers for a T Rex cam My cousin is torn. From everything Ive read, it seems like on stock cubes, no F/I that 1 3/4 is fine but 1 7/8 will make a little more. 10-15hp
Who has a TRex and what headers do you have? He has dough in hand but I dunno, is it really worth paying twice as much?
The car is
2001 SS
lid, cutout, flowmaster, 6 speed
Who has a TRex and what headers do you have? He has dough in hand but I dunno, is it really worth paying twice as much?
The car is
2001 SS
lid, cutout, flowmaster, 6 speed
on stock cubic motor go with 1 3/4". only go with 1 7/8" if you have bigger cubes or going FI. on a stock cube motor with 1 7/8" you will sacrafice some low end tq
hell maybe do the best of both worlds 1 3/4" stepped to 1 7/8"
hell maybe do the best of both worlds 1 3/4" stepped to 1 7/8"
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Thread Starter
Joined: Aug 2006
Posts: 731
Likes: 10
From: Albuquerque, NM
If he goes 1 7/8, he should make it worth his time and get a BIG cam then. Dunno. Either way, if he gets bigger it leaves room to grow...
EDIT- n/m I was thinking the TRAK cam, the Trex is a 242 for the win
EDIT- n/m I was thinking the TRAK cam, the Trex is a 242 for the win
12 Second Club
Joined: May 2005
Posts: 41
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http://bbs.hardcore50.com/calc/?mode=headerdims
I'm going to be running an MS4 with stage 2.5 LS6 heads and it says 1 3/4" is big enough. You do need to know where peak power is or is going to be in order to be acurate.
I'm going to be running an MS4 with stage 2.5 LS6 heads and it says 1 3/4" is big enough. You do need to know where peak power is or is going to be in order to be acurate.
http://bbs.hardcore50.com/calc/?mode=headerdims
I'm going to be running an MS4 with stage 2.5 LS6 heads and it says 1 3/4" is big enough. You do need to know where peak power is or is going to be in order to be acurate.
I'm going to be running an MS4 with stage 2.5 LS6 heads and it says 1 3/4" is big enough. You do need to know where peak power is or is going to be in order to be acurate.
12 Second Club
Joined: May 2005
Posts: 41
Likes: 0
I've seen dyno numbers saying otherwise, it all depends on the combo. I'm going to have spray on my car too, the only time you would see a big gain is if you spray a large shot (200+). And are you going to be spraying all the time?
Tech Resident
Joined: Jan 2006
Posts: 5,117
Likes: 3
From: Philly
1 3/4" LT's with merge collectors, hands down. Every dyno I've ever seen has lead me to believe 1 7/8" headers will gain nothing more up top and cost you lots down low on stock cubes. Unless you go stroker or a forged 347 with FI, I'd stay with the standard 1 3/4" headers. Otherwise, you'll lose too much exhaust velocity and lose a lot of torque in the process for no top end gain.
1 7/8" headers absolutely WILL NOT yield 10-15 horsepower gains over 1 3/4" headers on stock cubes. No way in Hell. You'll lose power before you gain power with primaries that size. Your motor isn't capable of pushing enough air to use that extra space efficiently. That'll result in poor exhaust velocity, retarding the scavenging effect and costing you lots of power overall.
Tony Mamo had a great dyno comparison of a guy swapping from 1 7/8" longtubes to 1 3/4" longtubes on a Corvette and picking up something insane like 30 rwhp. There were huge gains all over the curve from shrinking the primaries. Remember, if you don't need the extra flow area, it will do nothing but hurt you because everything slows down and becomes less efficient. Even with H/C and nitrous, I'd still go 1 3/4". There's not enough sustained power there IMO to warrant the extra flow volume.
1 7/8" headers absolutely WILL NOT yield 10-15 horsepower gains over 1 3/4" headers on stock cubes. No way in Hell. You'll lose power before you gain power with primaries that size. Your motor isn't capable of pushing enough air to use that extra space efficiently. That'll result in poor exhaust velocity, retarding the scavenging effect and costing you lots of power overall.
Tony Mamo had a great dyno comparison of a guy swapping from 1 7/8" longtubes to 1 3/4" longtubes on a Corvette and picking up something insane like 30 rwhp. There were huge gains all over the curve from shrinking the primaries. Remember, if you don't need the extra flow area, it will do nothing but hurt you because everything slows down and becomes less efficient. Even with H/C and nitrous, I'd still go 1 3/4". There's not enough sustained power there IMO to warrant the extra flow volume.
Last edited by ChocoTaco369; Jun 12, 2008 at 11:36 PM.
1 3/4" LT's with merge collectors, hands down. Every dyno I've ever seen has lead me to believe 1 7/8" headers will gain nothing more up top and cost you lots down low on stock cubes. Unless you go stroker or a forged 347 with FI, I'd stay with the standard 1 3/4" headers. Otherwise, you'll lose too much exhaust velocity and lose a lot of torque in the process for no top end gain.
1 7/8" headers absolutely WILL NOT yield 10-15 horsepower gains over 1 3/4" headers on stock cubes. No way in Hell. You'll lose power before you gain power with primaries that size. Your motor isn't capable of pushing enough air to use that extra space efficiently. That'll result in poor exhaust velocity, retarding the scavenging effect and costing you lots of power overall.
Tony Mamo had a great dyno comparison of a guy swapping from 1 7/8" longtubes to 1 3/4" longtubes on a Corvette and picking up something insane like 30 rwhp. There were huge gains all over the curve from shrinking the primaries. Remember, if you don't need the extra flow area, it will do nothing but hurt you because everything slows down and becomes less efficient. Even with H/C and nitrous, I'd still go 1 3/4". There's not enough sustained power there IMO to warrant the extra flow volume.
1 7/8" headers absolutely WILL NOT yield 10-15 horsepower gains over 1 3/4" headers on stock cubes. No way in Hell. You'll lose power before you gain power with primaries that size. Your motor isn't capable of pushing enough air to use that extra space efficiently. That'll result in poor exhaust velocity, retarding the scavenging effect and costing you lots of power overall.
Tony Mamo had a great dyno comparison of a guy swapping from 1 7/8" longtubes to 1 3/4" longtubes on a Corvette and picking up something insane like 30 rwhp. There were huge gains all over the curve from shrinking the primaries. Remember, if you don't need the extra flow area, it will do nothing but hurt you because everything slows down and becomes less efficient. Even with H/C and nitrous, I'd still go 1 3/4". There's not enough sustained power there IMO to warrant the extra flow volume.
I have a buddy with the Edelbrocks and he is very happy with them. Collector is a little large at 3.5''; but other than that he loves them. Best of both. 1 3/4'' and 1 7/8''. Supposed to create a pull in the exhaust.