I am 99% sure the KB intake is for the odd fire engines and would not work on the 78. There are several differences between the various years of the v6 intakes: 1. The PVC is not on all intakes. 2. The later intakes ports are taller and if using a miss matched intake it will not work well. I am pretty sure that even within the even fire engines there is two hieghts for the intake ports. I think it was 1979 that they went with the taller ports and the 78 only had the lower versions. This leaves the 78 as a one year only intake and head port size as far as I know. I went through this with the 78 3.8 in my Skyhawk. In the end I went with a set of heads off a 87 GN and an intake off a 81 4.1L engine. I ported the heads, gasket matched the heads and intake, and was going to add a turbocharger through a blow through carb but then lost interest and sold the car to build the twin turbo 350 Skylark. I have heard of people welding extra material to the early intakes then port matching them to the later style heads. If it was me I would find a set of heads and 4bb intake from a 4.1L Buick V6 and swap them on. Might as well just swap in a whole 4.1 engine at that point though. Even better I would prefer to swap in a Buick 350, less work for the HP and more importantly the TQ gain.
Just thought I'd through this idea into the pot. How about installing a supercharger and manifold from the supercharged 3.8's. You might have to modify the blower drive as well as plug the port injection bungs in the manifold. Also you'd have to fab a carb to blower manifold ( or convert to SFI). If you set the boost at about 5# you'd probably have 250 net HP. The SC 3.8 had 250 HP on 3# boost but they had SFI. That being said the SBB 350 swap will be the easiest, cheapest, and quickest option. Also if your v6 is in decent shape you can sell it to defray some of the cost.
I'm pretty sure the FWD 3.8's are 60* blocks not 90* blocks. That's why they are called Series II, and very little will actually cross over to the RWD blocks.
The Series II 3.8's are still 90*. The used them in RWD 90's Camaro & Firebirds as well as a lot of FWD cars. But since I don't remember what changes were made to the 3.8 to turn it into a series II it's possible that the supercharger won't fit on an earlier 3.8.
Here you go: Well KB says it fits everything but I'd bet if you really wanted it to work best with the '79 and up raised ports some port matching would be required but for the '78 and down it is just a bolt on. I don't think there was much difference between the odd-fire and even-fire heads up to '78. Try a nice small Holley or Edelbrock.
350 was a option in your car and your insurance company isnt going to know the difference they go by vins
