I know this has been covered many times, and I have repeatedly searched, but for some reason, my 'search' feature isn't giving me results off of 425.

-looking at putting 4 spd into 67 442 that was auto
-Street car, weekend cruise driver, that i want to have good performance when I mash it once in a while. It wouldn't be stay at red line very long, but it would probably taste it from time to time. It's got a low rear. stock intake/exhaust
-Realize you can get an adapter but have decided, based on numerous posts, to try to do it right and have crank machined
-Instead of tearing down the 400 that runs ok and isn't smoking, I'm looking at doing a replacement motor.
-Based on lot of what I read, the forged crank 425 sounded like good option.
-THEN was told "why do that, just do a 455".
-There is a ton of info, some of it confusing.
-I am reading it to mean a 67 Toronado 425 has .921 lifters and the 'new' cam bank angle, which lets me use the aftermarket cam. NOTE: IF that is NOT accurate, the basic question becomes a moot point, as I default to a 455.
-I realize a 455 is 30 cubic inches more than a 425
-I may have chance for a 67 Toronado 425 that would be usable. I definitely have a chance of a 72 big car 455 (with 88K).

To me, the 455 is probably easier and safer choice, but the 425 is a more interesting motor, but I don't want to get down a path of no return to find I made a mistake.

Question: Other than 'up to you', is there any reason to avoid the 425 in favor of a cast iron crank, big car 455? (.921 lifters $$) Or stated another way, is that 30 cubic inch difference going to make much diff?

Try to not torch me for asking the question if possible.....

Thanks

 

One man's opinion:

1. Don't worry about the cam bank angle - you just have to specify which angle you have, and they'll grind the cam the right way.

2. I'm not sure about the big lifters. I believe they can be hard to come by.
Mark (CutlassEFI) can set you up with whatever you need in that department.

3. The '67 Toro motor is a beast.
A '71 455 is a detuned smog monster.
If you're rebuilding, then it doesn't matter, but if you plan to use as-is, the Toro motor will blow away those 30 cubic inches.

- Eric

 

I like the 425's. More period correct for 1967 even though not a standard A-body engine. Pistons are more $$ because of less choice. Maybe a hair stronger of a stick shift street engine, more forgiving if you over rev, if you do miss a shift. 1967 C-headed 425's I've had were all 39 degree engines, or just stuff the 425 internals into a 455 block. Kinda like hitting a hornet's nest answering this guestion. Expect some disagreement. As always, JMO. Good luck, Ken

 

I'll be doing a Toro 425 in my '65 vista. It will be warmed over, but very easy to get it to the 400hp that I'm looking for. Also, a higher revving motor....would be a nice set up with a stick for sure!

 

Bingo.

As far as cams go, there are only 1 or 2 people that have roller cores for a 45, and they aint cheap. If that's the way you would want go.
.921 flat tappet hyd lifters aren't going to be a problem anytime soon however. My source not only redid the .921 roller but is also upgrading the .921 flat tappet as we speak. Should be good for any performance application.

 

425, no question.

TORO 425... better yet. ABSOLUTELY no question.

 

I think I would get the 425 because it will have better heads and higher compression bone stock. Either way you are having the crank machined. I would get ahold of Greg Rollin at Supercars unlimited. He is out of Beaverton Oregon and if you go to supercarsunlimited.com you can get his contact info. He is a wealth of knowledge and experience. Sells all the parts you need for this and has race tested most of them. I have known him for over 35 years and all he does is Oldsmobile.

 

I have used both, back in the 1970s. Today, it depends largely on whether you want to use it as is (condition is very important then), how much you want to build it up with aftermarket stuff, etc. I prefer the 425 overall unless you build the 455 all-out with light pistons, aftermarket rods, etc.