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First off let me say I have searched other threads for info, but none of them matched my car.
I have a 1979 L-82 but mine is supercharged. My main question is does it being supercharged change how the exhaust reacts? I'm planning on getting a set of headers and getting them on before the warm weather arrives. I have the stock manifolds BUT I do have dual exhausts with no H or X pipe in 2 1/4' diameter. Will I see a larger improvement over naturally aspirated engines? Will I see a difference at all? Can someone recommend a good set for a forced induction engine? Simply looking for power and fitting without dimples. I dont care about exhaust note or coating and whatnot. Thanks in advance.
I've had good luck with Corvette Central's 2.5 inch exhaust. From the crossmember back, it fits great, and a local shop can make a pipe from the headers to the crossmember.
I had Hooker headers on my 79 for a while until I got tired of cooked spark plug wires and switched to 2.5 inch outlet manifolds and 65 Corvette downpipes. The Hookers fit, but my heads had angle plugs and the headers required some dimpling for clearance (and still cooked wires).
On the dyno, we could see the restriction of the manifolds on my car around 5800 RPMs. My engine is naturalyl aspirated, so you'd probably benefit from the headers since you're moving more air.
Those manifolds are holding you back some..id say any header with a 2.5 dual exh will get you something you can feel. The X and H isnt needed, just my .02 guys will argue all day about it and eventually mention nascar.
You should be looking at a minimum of 1 3/4 primary tube headers that are ceramic coated. I also used 'DEI' heat wrap on the headers to keep under hood temp down. The exhaust system is a 'PYPES' 2.5 with X pipe. I think they are stainless steel. Excellent fit. Three mufflers to choose from, I chose the two baffle. A friend has the 'Violaters', to loud for the street IMO. Running a 'Vortec' V1 max 8 psi boost. T
With headers and free flowing exhaust system you might be approaching 400 hp. It takes a pulley change to get 8 psi and larger valves heads to approach the claimed 450 hp level, but then you are rpm limited because you can exceed the blower rotors rpm's
as to headers and having to dimple the pipes. That all depends on the head manufacturer. I installed 1 3/4 hooker SC headers in my 79 l82 with modded 186 casting heads and later dart pro 1 aluminum angled plug heads without a problem. I later on down graded to AFR 210 heads angle plugs and I had to dimple 2 pipes for plug cap clearance I was a little pissed about having to do that to nice headers. afr heads actually made plug changing more time consuming because you can't use a socket because of the bad plug position. The actual cure for afr heads and plug clearance is to cut the flange off primary pipes and add one inch of 1 3/4 pipe straight out and rewelding them together
as to wires burning. It never happens if you install quality racing plug wires and route them correctly
as to H and X pipes decreasing exhaust system back pressure is a good thing how ever it is done. The biggest benefits of them is that it doubles the frequency of the exhaust note and decreases the total DB
my advice is to look at your exhaust system as a lifetime investment and do it right the first time. Buy quality 1 3/4 headers. You can only thermal wrap stainless steel. Trying to route the pipes back from headers through the stock tranny cross member is stupid and shows a real lack of for thought. You can make or buy a custom tranny cross member like the BTO overdrives. Where the pipes pass under the C.M.
You want the pipes coming straight back from the header collectors. Do it once. Any quality muffler shop can install a 3 inch pipe system the first time. Because your not going to be happy with a wimpy sub 400 hp later on. So if you do it right now you won't have to redo it later
They are stainless steel with 1 3/4 to 1 7/8 inch primaries (depending where you measure, not 2 inch as claimed) and nicely made. I did have to slightly dimple the passenger side header to clear the upper control arm bolt but very slightly. The driver side fit perfectly and have no issue with the spark plugs but did use the accel 9000 ceramic boot plug wires since the boots on a few cylinders are very close to the headers but not touching. The heads are AFR's:
I also had the headers ceramic coated locally so I did not have to send them out for the coating:
That picture is from January 2017 and they still look exactly the same today (yes the top bolt is not tightened in the picture but was corrected).
All in $525 for the headers with the ceramic coating.......pretty much the best value out there..............for a stainless steel header ceramic coated with large primary tubes for a SBC.
I am finally get rid of my Monza dual tip Turbo mufflers for these 84-90 C4 Borla mufflers S type straight throughs.....:
Since I have a L-82 355 now with AFR aluminum heads, roller cam, and 10.2 compression, I am trying to maximize the exhaust flow as well.........All in for this exhaust I'm probably $1,500 for the complete exhaust....headers, 2.5 stainless pipes and the Borla mufflers......
It's a sickness I have had since high school.............
I have Hooker Super Comp headers on my '79 and they fit with zero modifications whatsoever. I have run them with the stock steering, with Speed Direct rack and pinion, with stock heads, and with AFR 220's with 1/4" raised exhaust ports, and have never touched the headers. They just plain fit. With that said, you will hear from a lot of guys that Hooker is having quality control issues in the last few years. Mine are good, but I've had them for 20+ years. As for the exhaust system, I have the Corvette Central dual exhaust setup, and again zero mods. The only mods were to connect the headers to the exhaust. If your 2 1/4" duals are in good shape, I'm not sure I'd be in a hurry to change them. I would certainly add a crossover pipe, but I'm not sure the 2 1/2" will make a noticeable difference. And FWIW I run mine through a largely stock crossmember (I moved one of the holes over a couple inches when I was running the 700R4) and its a very clean install. No need to change the crossmember just to accommodate the exhaust.
I too have Hooker Super Comps on my 4 speed 79. No fitment issues at all. I've burned a plug boot, but it was my fault. I didn't catch that my wire was touching the header pipe. A simple twist of the boot to make it come in at a different angle solved that problem. They were on the car when I bought it 12 years ago and I don't know how old they were then. I've had them ceramic coated and can say it definitely made a difference in heat radiating from them.
About 15 years ago or less, a friend who modified corvettes a lot, let me have a set of the same Borla's that he had used for a couple hundred miles for $50. Then, another $65 to have them installed and now have these on my 82 for just over $100. Very nice sound.
About 15 years ago or less, a friend who modified corvettes a lot, let me have a set of the same Borla's that he had used for a couple hundred miles for $50. Then, another $65 to have them installed and now have these on my 82 for just over $100. Very nice sound.
Look up 84-90 Borlas S type 2.5 inch pipe with the square tips if you want to be stunned.......................sticker shock!
I too have the Hooker Super Comps (73 vette, SBC), real easy to take in and out. At 5 psi, 2.5” exhaust will be fine. My 2 cents, Ceramic coating and an X pipe should be in your future.
Look up 84-90 Borlas S type 2.5 inch pipe with the square tips if you want to be stunned.......................sticker shock!
Got the mufflers without the tips. Had to buy some chrome tips. Looked them up and they are really expensive. Understood they were about $250 each when I got then, probably 12 - 15 years ago. Testimony they stand up to use. Still look like new. Though I have sprayed them flat black with ultra high heat paint to hide them from the rear. Do not like seeing mufflers themselves.
02-10-2018, 11:46 PM
Performance exhaust questions
