I'm putting a 2.5" T/A dual exhaust under my '65 Gran Sport Skylark. Sticking with factory exhaust manifolds so I would like to get a mandrel head pipe/downpipe from manifold to new exhaust. Probably want to eliminate the heat valve on pass side manifold too. Anyone had any luck finding a good flowing piece for this? Car has original 401 and ST300 in it. Also, what mufflers make a nailhead sound good? Flowmaster? Walker? Thanks is advance to all the Nailheads out there!
One side already dumps out parallel, so all you need is a straight pipe with a flare to mate to the manifold. There was a board member making heat-valve eliminators a few years ago. Or just take the butterfly out of your original and plug the shaft holes. For the passenger side dump, a 45 degree bend will work. Flare the end to mate to the manifold. The stock manifold outlets are only 2" in diameter, but flaring a 2-1/2" pipe to mate with it does work....the seal isn't very wide so it has to match well. ie, hand fit it. I have a 2.5 inch Poston system on my blue car with Walker Dynomax mufflers. It has a mellow sound that I really like. My red '66 has a Magnaflow system that sounds a little wild at idle (good), but gets annoyingly loud at cruising speeds....especially any time I even (barely) touch the gas. It'll be getting Walkers in the Spring to quiet it down. BTW, the Magnaflow system came with several tailpipe options. There was enough tubing left over to connect it to the manifolds.:TU: Have you visited www.65gs.com yet???
Maybe building 2 1/4" headpipes would be a good compromise from 2" manifolds to 2 1/2" exhaust. I have a 3" T/A system under my BBB '65 Skylark with Walker Race Magnums and that system fits great-sounds like thunder at idle or WOT. I'm leaning towards the Dynomax for the GS's system though, and T/A does a nice job with the tailpipes-nice OE look to them. Thanks for your info and suggestions Walt!
The stock exhaust has 2-1/4" headpipes but they are squeezed down to 2" in the few inches after the manifolds. Not sure if exhaust shops can do that, but Gardner Exhaust does it for their repo systems. TA has tailpipe extensions for the 64-67 cars right? I see too many 64-67's with tail pipes that don't reach the bumpers. looks bad, IMO. Dynomax's sound great behind a Nailhead.....especially with a lumpy cam!:TU:
I did what you're talking about - On my 65 I used 2 1/4 pipe flared at the left manifold and welded to a generic plate on the passenger manifold where I delted the riser plate. the passenger side necks into a generic 2 1/2 mandrel 45 degree bend, and driver's side necks into straight 2 1/2 pipe about 6 inches back from the manifold. that hooks right into the Pypes A-body sytem with an X pipe, I sold the Pypes mufflers and used the Wallker Dynomax's like WKillGS, then used Pypes downturns for the tailpipes. Looks stock, Idles quiet, sounds great at full throttle and gained a tenth or two... My only regret is my car had a cool quiet almost flathead/glasspacky like rap with the small stock exhaust. Thats gone now and I miss it - it was unique. I sounds like any other muscle car now.... ---------- Post added at 05:29 AM ---------- Previous post was at 05:23 AM ---------- I did what you're talking about - On my 65 I used 2 1/4 pipe flared at the left manifold and welded to a generic plate on the passenger manifold where I delted the riser plate. the passenger side necks into a generic 2 1/2 mandrel 45 degree bend, and driver's side necks into straight 2 1/2 pipe about 6 inches back from the manifold. that hooks right into the Pypes A-body sytem with an X pipe, I sold the Pypes mufflers and used the Wallker Dynomax's like WKillGS, then used Pypes downturns for the tailpipes. Looks stock, Idles quiet, sounds great at full throttle and gained a tenth or two... My only regret is my car had a cool quiet almost flathead/glasspacky like rap with the small stock exhaust. Thats gone now and I miss it - it was unique. I sounds like any other muscle car now....
they have the short 14 inch and the 20 inch body dyno max, the big ones flow better and have a softer sound. i have been running the xs pro borla nice sound not to loud but with great flow numbers. the flow masters (all the time) and sometimes the dyno max on some combos have drone.
I have Magnaflows on my Buchev pickup. I like the sound. I didn't purchase them by application, but by the size that I wanted. I don't have access to my parts file which is in MA (I am in FL) but as I recall, my Magnaflows are fairly large in diameter and length. I wanted as much of my exhaust system as possible to be Stainless Steel.
Hi, Mine I did not have the heat valve so we simply installed a doughnut in the manifold and flared a normal 2.5 inch pipe to fit it make sure you go with a quality mufflers as I got some flowmaster knock offs and there is a lot of drone under decell but mine's a stick so may not be an issue for an automatic Regards,
Thanks for all the input-I think I'll go the longer case Walker route. The car is a great cruiser/commuter in the fair weather months so mellow exhaust is what I'm going for. Yeah I had those knockoff Flowmasters under one of my cars years ago-I think I made it a month before they hit the dumpster. Thanks again to all that shared input and ideas for my exhaust project-it'll be soundin' sweet for summer!
