suped up 6

[1967cuda]

Can some one tell me the advantages (in terms of power and performance) of boring out a 225 and installing a 4-barrel carb and headers?

If I did that, would I also need to upgrade my transmission?

Thanks!
Thomas

 

[runvs_826]

Boring out the slant doesn't have huge benefits. Even if you over bore it .080 you've only gained 15 or so cubes. Wiesco is offering some new pistons for the slant, but probably won't fit your needs vs. cost.
The four barrel is probably a little much from the sounds of what your looking for. The super six (two barrel) will most likely fit your needs if your looking for a little more spunk with bolt-ons.
If your going to be rebuilding the whole engine, I would recommend a few other things. State your goals so you won't be disappointed later. Research ENGRBLDR oversized valves on E-bay. The Erson cam group buy. These last two would have major benefits compared to an unneeded overbore. If you need to clean up the bores, just take out that much. Good luck!

 

[2 Darts]

Think of the engine as a giant air pump. The more air you can move through the pump, the more power it produces. Headers & 4-bbl carb are two ways to help it. Other things are cylinder head porting and increased valve opening through camshaft changes and/or larger valves.

You didn't say which transmission you were working with. The 904G and the 833 are plenty stout. The all-synchro 3-spd manuals are fine. The ones without synchro on first would handle the 273 2-bbl ok, they just aren't as easy or fun to drive. Hope this helps.

 

[66aCUDA]

With a slant engine the BIGGEST gains are to be gotten in the head. We routinely mill.100 off of the deck or head and put 1.70/1.44 OS valves in. Choices are limited for bolt on parts. As RUNS says a super six may get you where you want to be. A 2 bbl will be ALL the slant needs until you stick some major coin or work into the engine internals. As for over bore you can safely go to .105 or even more(check for core shift).
Frank

 

[1967cuda]

Thanks for all the input. I would eventually like to rebuild the engine, but since it runs for now, I think that will be the last thing I do; it needs new suspension, and desperately needs to be rid of rust. I want to rebuild it for a couple of reasons; I want the experience and satisfaction of doing it myself, (I've helped out in the past with rebuilds), and I would like to increase the performance. But, like I said, that won't be for a while.
Thanks!
Thomas