1968 289/302, T18 4 speed, Spicer/Dana 60.2 rear axle / 3.54-1 / Limited Slip, Edelbrock Performer, Holley 1850 4bbl, a medium cam with max rpm runs around 3K.

Faced with a dilemma; replace Hooker Long Tubes for Shorties, at a cost of between $300 to $600, or use the original exhaust manifold? Considering the engine, transmission, and rear axle configuration would there be much of a performance improvement for the additional cost??

Finally, if I use the original exhaust manifold I came across 2 gasket replacements, both described the item as a Header Gasket, would this be one in the same?

Comments, Suggestions appreciated.

 

Max revs 3K? That engine should run to 6000 and like it.

Stock 302 manifolds are ok for what you are doing. Avoid early non-hi-po 289 manifolds. If what I have read here is correct, the later 302 manifold is closer to the 289 hi-po manifolds. A little swoopier than the early 289 manifold.

Or run the shorties.

I had a 289 with flat tops, an RV type cam, a stock iron manifold, headers and good valve springs and it would run nicely to 5500. (It would have run nicederly if I had a better carb than the 390 Holley)

Stock manifolds did not use gaskets. If both surfaces are flat, you don't need them. (a big IF for stuff this old....)

 

Seem to recall exhaust manifold came off a 70 Torino engine, in 2008,replaced the engine with a created 68 289/302 and went with the Hookers when I swapped engines.

Spent afternoon with friend who has some mechanic experience, primarily high performance engines, who made same comments as U, felt the engine should be running at least 5k with no problem. Suggest perform couple test to try and pin it down. He's an A type, suspect within a couple days it will bother him , method to my madness, and drop by to help figure it out. He tried to explain timing and advance curve, did not make any sense to me, but apparently he has a timing light that can monitor both while adjusting??

Greatly appreciate your comments/suggestions!!