I have a 67 400 Convertible, quadrajet TH400. Runs great, but looking for more kick. Any suggestions on a cam/lifter/spring set up? Not a strip car by any means. The pistons were reliefed when I got the car (670 heads). Should I consider getting back to the original compression?

What are your fuel limits/availability? With a vert (400+ weight) I suggest a taller gear (3.23-3.55)

Keep the 670 heads, machine the seats down to accept a 1.71 installed height, keep the CR the same with 104-108 octane and go with an 068 regrind from Comp Cams.

IMO Stock compression would put you right where you want to be with 'more kick'. You will then need a mixture of racing fuel and super unleaded. It's available here but is it where you are? One way to go that you could stay right away from the machine shop and/or pulling the engine is to get yourself a set of aluminum heads. You would be looking at about what it would cost you to swap pistons(parts & labor) but you can swap heads yourself on a weekend.

would octane booster added to 93 be an option?

It would be an option with your choice to return to stock compression. I would be using it if and when the racing fuel pump gets closed down.

most octane boosters wont bring your octane to an acceptable level. this is my opinion only! have had experiences with this where my 460 ford will not run properly with boosted fuel. put in high octane fuel and it runs like a raped date!

a set of KRE heads would give you the added kick you desire. also have you considered taller gears and a trans kit? the trans kit would give you the grab your short feeling your looking for and keep your costs low. the heads are a different story!

you could go with a cam but once your octane needs go up, the fun factor wanes slightly because you ten not to drive it as much because it is more costly to put your foot into the juice!

as i was always taught, start with the cheapest thing first and go from there! go till your satisfied with the results and make sure everything works well together!

andy

I agree that the octane booster isn't as good as the real deal. Here's a thread that lays out some options;
/forums/ubbthreads.php?ubb=showflat&Number=45785&page=0&fpart=1

rear gears is a good place to get more 'kick'

Rear gears and a good first gear (especially if you have a two speed)!

As always, great information. God, I love this web site

Going to a "bigger" cam will reduce the need for high octane, not increase it. A cam with about 215/225 degrees duration @ .050" and about .450" lift and 110 to 112 LCA works very well in a street driven Pontiac 400 with an automatic. I've had good results with Comp and Crower.

Check through this list of Pontiac cams and you'll see that there are a few options. The factory cams have a wider LCA and shorter lift than the aftermarket cams.

http://www.classicalpontiac.com/restoration/cams.html

A cam any "larger" than described above will likely require a converter change.

My 2 cents...

I agree about the rear gears. I put a 3:55 posi in my Bird this year and what kick it gave it off the line. Not to bad cruising either, around 3 grand at 65 mph. Cant wait till I convert to a 4 speed!