Exhaust. RA cast iron re-pop exhaust manifolds, 2 1/2" duals.Out of curiosity, after everything is running smoothly and the tune up is complete, what performance mod would be my best bang for the buck? It's a 400 engine with edelbrock heads, and a Holley double pumper carb. Everything else is stock.
LOL, you need to get out more often. Any Pontiac enthusiast knows what 4:33's are. They are the factory mandatory rear axle gear ratio on the 1967-'68 Ram Air powered GTO's, and optional after that. All out racing gear and not great on the highway. Will wake up any engine due to the acceleration factor they provide. So cheap means to go fast, but gas mileage is non-existent, uncomfortable RPM's on the highway, adds additional wear to the engine due to use of hgher RPM's at lower road speeds, may whine, probably will have traction woes, but...........your car will scream when you can hook-up.What do you mean by this?
If you changed the heads/intake/carb, but didn't get a cam to go with it, you will probably gain one heck of a lot from that.Out of curiosity, after everything is running smoothly and the tune up is complete, what performance mod would be my best bang for the buck? It's a 400 engine with edelbrock heads, and a Holley double pumper carb. Everything else is stock.
That’s why I was wondering about the tune up,get b out of there before he has to get a 2nd mortgage to get this thing runningAm I the only one that puckered up when he said the shop wanted $350 to rebuild the Holley? Maybe I'm out of touch but that seems terribly high.
650 CFM is a nice mother-in-law carburetor, but going the wrong way for performance. Maybe something in the range of a Holley double pumper -- oh wait!
Car probably came with 3.90's from the factory, but I've seen quite a few 3.55 special order rears. Pretty high ratio for performance work with a close ratio trans. Figure the 3.55's and close ratio is about the same first gear ratio as a wide ratio trans with 3.08's.
Apparently, REJET is not a word! This damn computer has "corrected" it twice!Yep, need to find a club! Check GTOAA for a local chapter, or start talking to guys at car shows with similar vintage cars. You'll quickly find out who the local ripoff artists are, and (hopefully) who the local heroes are. And there's usually at least one "motorhead" in the club who will show up on a Saturday and hold your hand while you fix it yourself.
Sadly, a lot of "mechanics" and "garages" are as lost as you are when it comes to working on cars with points and carburetors. Even more lost when it comes to modified cars.
How was the car running before you started working on it? If you still had points ignition and it was a little rough, it was probably time for a full tuneup. If the points were marginal, and the plugs were gapped at .045, probably just didn't have enough grunt to fire the plugs. I like Pertronix ignition conversions. Pontiac Jim will argue.
Points ignitions require a ballast resistor or resistance wire to the coil to drop the voltage from 12v down to about 8v. There are three different Pertronix ignition conversions (plus full distributors). The original Pertronix is just an electronic switch that replaces your points and will run okay on the (stock) resistance wire. Pertronix II and III are happier with a full 12 volts, which requires some wiring changes. And of course we don't know for sure what brand conversion they used.
If you didn't have a fuel problem before, you shouldn't have one now. A light tweak of idle speed and mixture is usually part of a tuneup. Ignition timing also affects idle, and should be set before final carb adjustments.
Another big advantage of finding the "motorhead" in a club is that you can get advice from someone who's not trying to sell you something. Any bonehead can bolt on a carburetor. Even a newly rebuilt carb will require tweaking in for best performance. And it takes a minor genius to reject a carb to match a modified engine and actually have it run better. And there are Holley guys and Quadrajet guys who may be proficient with one or the other, or both. If the mechanic you've found is preaching Quadrajet, he may know what he is doing.
Your car came with a Quadrajet. If its relatively stock, it would probably be relatively happy with a parts-house rebuilt carburetor. Pontiac spent a lot of time getting it right.
Or you could spend an extra $500 (or more) and get a correct restored carb from one of the specialty houses. Better? Probably. Worth it? Maybe.