couperdecar

Has anyone had any experience with the Doug Thorley "Tri-Y" headers?
And does anyone know if they'll fit a '79 vette? Doug Thorley catalogue says they fit up to a '77 , but Summit says they'll fit to an '81. I've got the L-48 with a slight cam - .454 lift , 700R (nice) , 2500 stall converter and 2.5" duels and I'm about to stick on some Vortecs. These headers are 'supposed to' be great from idle to 4500 rpm. I'm looking at gas mileage (who isn't - we're paying $4.07 /gal up here in Canada) and a little extra hp (of course) Anyone?

Ganey

Tri-Y are for mild setups. From what little info. is given, your cam should be good to at least 5000+.
Headers can increase mileage.
The Dynomax Corvette SB Cerama-Coat headers fit & flow great, much better than is commonly known. I have been rec. them & many have them now.

Guru_4_hire

Tri-ys can be for performance applications but you have to pay for them.



You gotta pay for them though.

couperdecar

thanks guys. I've really been disappointed with the torque of this engine. The car has NEVER been able to spin the tires. Not stock , not with the cam install , not with the 700R install ! The cars got 3.55 gears and with the 700R I figured I'd have all kinds of go. Nope.
I'm not so much after hp , but after torque - the kick in the but off the line kind. I'm not so sure the 2 bolt main L-48 can handle much over 4500 rpm , so thats why I was looking at the Thorley headers.
Can the "stock" crank/pistoned L-48 rev much passed 4500 rpms?

my mach 5

Check these out: http://www.stans-headers.com/gm_headers.htm

a1sensei

A 2-bolt main can handle 400 hp (and often more). It should also handle well over 4500 (6000?) as long as it is in good shape. After you replace the exhaust, if it still does not spin the tires, you need to look at the tuning (you might want to check that now come to think of it!). 3:55 rear gears and 3.06 1st gear on a 700r4 should burn rubber! God bless, Sensei

toddalin

I have Thorley headers on my '64 (not the tri-Ys though). Great headers! Probably about the thickest flanges and tubing in the business. When I put them on (replaced the rams horns) the car was quietier!

couperdecar

thx again ! I'll have to give Stan a call @ Stan's Headers. He might be a good alternative to Thorley. I'm kinda stuck on this tri-y idea. It seems to make sense. I don't think this car and I will ever be at the track or zippin her over 5000 rpm much. Just want to know that next time some Triburon tries to take me on , I could kick his butt 'if' I wanted to.

Fevre

Either there is something seriously wrong with your tune (carb and/or timing) or you are seriously over-cammed if you cannot spin the tires with a 700r4 and 3.55 gear.

couperdecar

cam is .454 lift 272/272 advertised duration and 216/216 @0.05

I've got a local shop putting some Vortecs together , then I've got to
find a manifold , get some headers blah blah blah. Anyway I've had
the car scoped/tuned. Mechanic says the carb is tired, could use a
rebuild. I'm thinking just popping a 600 - 650 Holley on it (When I
get some more $$$ that is )

I just missed buying a ZZ4 by a day. Local guy had one for sale for
$4 G - still in crate. I phoned down to chevy dealership and they
want $7900 + taxes. (Canadian) Aughhh too much !!! I'll just keep plugging away with the bolt ons.

Tim H

Waste of money.
For your setup just get the cheap Summit headers for $90 bucks and spend what you have left on a ton of little upgrades that add up to alot of power!!!