Originally Posted By: Lifeguard
Originally Posted By: TonyPa


I truly wanted dual exhaust, with quiet mufflers though. Nothing too noisy. So the offy intake, and langdon splits will work together?

I didn't know if there was any gain from using a 292 manifold. I did read someone else did that.

Electric fan would be nice honestly. I never hooked one up from scratch. But can't be that hard.


You're welcome. I'm in the same situation. I bought a non-running '78 Camaro with an inline, 3spd manual, and an open 2.73 rear. Original intent was to swap a V8 and 4spd or TH350, but I played with the engine a bit and got it running. I got a lot of attention for the six from bystanders and online, plus I went through a financial hardship, so I decided to investigate keeping it that way and working on it.

Yeah, not as cheap as headers, carb and intake for a small block but still around a grand for the main stuff. Yeah, the Langdon Stovebolts will work with Offy when you use the heat plate hooked into the coolant to warm the intake.

I was missing everything from the cat on back, so I swapped it out for the '77-'81 Z28 cat back dual resonator setup. Quieted it down for the condo association. IntegratedJ is putting together a dual 2" that Ys into a 2.5" down through a single transverse muffler on his '78 Nova with auto.

Your exhaust manifold is a single 2" outlet. The later 292 manifold came in two versions, the SD with 2.25" outlet and the HD version with a 2.5" outlet. For a daily driver or mannered street cruiser with a smaller cam, a dual 2" setup or a single 2.5" exhaust is the right size.

I have my electric fans out right now, and I'm using the 3 blade clutch fan. But when I flush my cooling system and replace the thermostat next, I'm going to put them back on and run a wire from a connector at the electric choke to the relay so that the fans will stop running when I turn the engine off.

The cylinder head is a big part of upgrading the inline. There's a lot of machine work involved to add lumps, bigger valves, multi angle valve job, and deck the head to reduce CCs. The cylinder head is about $800 to $1200 depending on how much of the work you do yourself and how cheap your machine shop is.

Sounds like you want to do little by little as you can afford it. Probably start with HEI first as that's your cheapest upgrade, or adding electric fans. Then you have a choice between doing the exhaust or intake next. Probably head and camshaft last. Beyond that, you can try to raise compression with pistons, but unless you can find some old 307 factory flat tops or TRW forged flat tops, the only option is the Ross pistons which are pricey. Oh, and sounds like you want to swap out the 3.08 posi gears for some 3.42 at some point.


Yeah that's the problem is money of course. I guess it all takes time though. I do see that the head is truly a big improvement for power. I pulled my valvecover to replace the gasket and put the numbers up on the Nova forum since I could not find anything even close to my number.
Seems when he replaced the head according to a fellow that found my numbers online somewhere, he thought my head might be a 1969 292 head. Which I guess is no increase on anything. I can put my nnumbers up. I never found rhrm online.

I do know my gears are holding me back. Truly great on the highway. But i don't do much highway driving. I seen summit sells posi gear packs if thats what their called. About 500 bucks or so. Never installed a complete set up.

I seen you have to really dial them in or something. Many have seemed to change their gears before doing anything and noticed an improvement from that until getting the motor reworked.

Going to a 3.43, is there a pretty good difference from the 3.08? Or is 3.73 better? Or too much for a TH350 3 speed at 45mph cruise?

The parts are pricey and will take time. But would be nice to grab about another 50hp.