No one is making a header larger than 1 5/8” currently. I saw one set of 1 3/4” primary Nailhead headers for a 64-66 GS in all the years searching Nailhead parts (should have ponied up for those!). So anything larger would have to be custom. There are sets of Nailhead flanges and stubbs in larger sizes if you are willing to make your own. The 1 5/8” headers for the Nailhead will not be a restriction until there is extensive porting and larger valves. Big block headers are not needed until you flow like a big block. Cheryl
Tom Telesco told me the headers on Bob Quiggs 66 are 1 3/4". They have to be custom then as the heads are heavily ported. In the Motor Trend mag 1 page pic of the car they looked even bigger, as the curves plays tricks on your eyes..
My '64 Riv. with 180K on the engine went a best of 13.902@98MPH. At 4400lbs. 3.90 rear gears, old 1970 M & H slicks, my "prototype Rockers". a 750 dbl. pumper Holley, (which is not supposed to work on a heavy car) an adapter plate for the Holley to the manifold, it worked well enough to occasionally pull the left front wheel which I have pics of & video, exhaust manifolds ported out to match the head ports I did when I was 24-26, modified intake to MY liking, low compression of around 8.2-1 & other things I don't remember. Best at the wheels was 272HP. Have the paper work around here someplace. My feeling it's pretty impressive. Tom T.
I got my '55 Special 4dr hardtop with three on the tree stick and a warmed-over 264 into the 17s. Not fast by today's standards, but impressive in the early '60s.
My engine has stock GS exhaust manifolds with no modifications or port matching, into a 2.5 x pipe system. The intake isnt port matched per se, Tom just radiused some of the edges so there'd be a smooth transiton with any changes in alignment from decking.
Really is a well thought out stock build. Great numbers for a heavy loaded convertible.. Suspension specific's included
Thanks, honestly its the suspension that makes the car. Tom and I worked hard on that. If you cant put it down, all the HP in the world is meaningless.
