by Chief_Runs_W_Coyotes » Fri Oct 09, 2020 9:42 am
Thanks for the comment DarthVega, but the pictures are at selfie angles, you know the ones..."turn your head till you look thin". Well, with this car its "angle till you don't see the rust"! So I have been daily driving this now for a couple months and have been really enjoying it! It has slightly reshaped some of my plans for the car, and sadly also lengthened my timeline by a lot, as it's my only way to work at the moment. So I thought I would take a few minutes and touch base with thoughts and opinions on a few things:
1. The Duke - drives a lot better than I expected, part of this might be the fact that it's a four speed car and I shift normally above 3,000 rpms, but it manages to go pretty well. It has been dead reliable every day. There's obviously room for improvement and I'm still working out the plans but when done I should be around 140 hp and still reliable. All in I'm looking to keep it under $1500 in upgrades to the engine as this is meant to be a budget build. Currently looking into the following:
A. Head work: deshroud the valve area, enlarge all ports, increase valve size, and switch to Z-28 springs. Should be about 80% of what the SD-4 heads were.
B. Camshaft: swap to a 272 grind and switch to the aluminum drive gear that's used on the 235/292 straight sixes. The micarta gear makes me very nervous lol
C. Exhaust: long tube headers from hedman meant for the Jeep application (the 81 jeep 2.5 was the same as my engine). The headers will likely need a little modification but should help exhaust flow greatly. Followed up with a cat delete and I'm still undecided on mufflers. I'm trying to keep that old school vibe so I'm thinking glasspack and a resonator.
D. Intake: biggest lump sum can be found here...double side draft webers. I'm most likely going to have to fabricate a manifold as the duke manifolds that I have seen were actually SD-4 manifolds which were slightly different in design (other than the larger ports).
E. EGR: with the header and intake change this will be deleted. Gas mileage will suffer some but not too bad.
F. Other: new plug wires, all top end gaskets replaced, ARP head bolts (currently missing one, it came that way), engine repaint, replace all rubber everything.
2. Transmission - the short gears provide a fun driving experience, most of the time. The only real issue I have is highway cruising, around here it's 70 or more for average highway speeds which is 3,000 rpms and up with the old four speed. I have come across an article about using the 3 speed saginaw's overdrive tailshaft and replacing the four speeds tailshaft with it to get a four speed overdrive. Google hasn't provided much luck on sourcing one of these but I plan to keep an eye out next year at swap meets and the like.
3. Ride Quality - the old bird rides about as good as any car I have ever been in. It is a little soft but corners well. I plan to stiffen and lower it a little with a spring swap and new shocks. I hadn't planned on replacing the springs but the drivers side rear of the car sags about an inch and half and I don't think shocks would be enough to correct this. The plan is to buy stock replacement springs and cut off a coil and a half, kyb replacement shocks should still function properly with that short of a drop. The other issue I have with ride is that above 70 it feels like I'm on ice, this is likely a caster issue which I will have investigated shortly, but this car could use some functional aero. I have been searching for a front chin spoiler that was more than decorative and have come up empty handed. I think I will need to put my fabrication skills to the test and make one the way I want it. Rear spoiler is still undecided between a few options.
4. Interior - still haven't done anything here yet, I'm undecided on whether to reupholster the factory seats or swap them. Radio is going to get replaced with a retrosound, and I'm looking for some old clarion shelf speakers for the rear. Also still trying to decide the best cupholder placement as door hanging isn't my favorite but it's not horrible. Steering wheel is going to get replaced with a classic Grant unit with a wood grip 14" diameter to give me some more room to get in and out. I'm glad mine has the tilt option otherwise I couldn't get in at 6'4" tall.
If you have any advice on the above ideas or options to look into, or sources for parts, please let me know. This has been a slow build process and will continue to be as such but hopefully with tax season around the corner I can get more done (or get the body work done if I can get my other car running again.)
1979 Pontiac Sunbird (currently undergoing restoration) with the old duke and a 4 speed