As in my previous post I have a friend who is willing to sell my a 76 455 that is out of a 98. It is running. I also found a 65 425 super rock ultra high compression engine for a 100 dollars. The 425 is apart. Here are some pictures. I do believe it is the 470 tq and 370 hp 425. What are your thoughts?

 

All things being equal, a factory stock ultra HC '65 425 would run and hide from a factory stock smog-era 455. I'm guessing either engine would require a rebuild, though, so the extra cubes of the 455 might erase that advantage if it's carefully built.

 

+1. The 425 is a much better motor. [edit: somehow I had typed "455"]

That being said, if you're going to do a total rebuild, it doesn't matter, because you'll be changing all of the 455's weak parts anyway.

Finally, the Vxxxxxx engine number corresponds to a '66 400 (usually a 4-4-2), not to a '65 455, so you may be looking at a frankenmotor there.



- Eric

 

Damn I wish I could find a 425 for $100, can't go wrong with either or in my opinion. Can I buy one of those lol

 

If you are going to build it from scratch go 455. Built with equal components the bigger engine will always win. If you are just going to run it in stock configuration go with the 425 as it already has higher compression and better flowing heads.

 

The picture is of the 425. I was looking at it and it looks like a N to me but I know they didn't put a "N" on it. So it would have to be a "V". Thank you for the information.

 

Easy buy them both! A complete motor for $100 even in pieces is a deal. Run the stock 455 and build the 425 as you can. Or sell the 425 parts to help fund the 455 build. Either way you can't lose.

 

x2

 

Buy them both and sell one to jphil350olds.

 

The 425 is the better engine overall but the 455 will be easier to find parts.

425 has the better crankshaft and bore to stroke ratio but, unless it's a Toronado block, it also has the disadvantage of 45 degree lifter angle as well as oversized .921 lifters- meaning neither cam nor lifters are available off the shelf.

Take a wire brush or a flapper wheel to the 425's engine # pad and see what it really says. The first 3 "1's" look weird to me.

Or you could use the 425 heads and crank on the 455 block and have best of both worlds, without the 425 lifter angle issues.

 

I often hear people on this site talk about the advantage of the 425 forged crank over the cast 455 crank. Unless you plan to make 600+ HP it really is not an issue. Most guys on this site are restoration or mild street car kind of guys. They will never see the benefit of the 425 crank over the 455 crank. What they will see however is a bit less bottom end torque which is exactly what they are looking for.


<<<< This car has a cast crank and has run 11.60 @ 116mph. That translates to just shy of 500hp @ 3825 lbs. I also have over 200 11 second time slips to support the claim that crank durability at this level is not an issue. If it makes you sleep better at night knowing you have a forged crank in there then knock yourself out but know that the only thing you're gaining is added expense.


Now when you start making BIG power that's another story.

 

What's the cranks weight difference Chad?
I've heard it before, just can't remember.

-pete

 

Teach me something. My 65 425 98 engine has .842 lifters. I thought it was the Toro engine that was different with the angle and the .921 lifters. The 65 CSM lists the 425 lifter dia. as .842.

 

Yeah. I have a 'D' block 425. It has the .842 lifters. I checked. I don't know if it came out of a Toronado. it was hot tanked and no paint is left. I was told by seller it was a '66 block. Is it probably a 45 degree cam angle block anyway? Second: I have some '66 'B' heads. Will they match the pushrod angle? I'm very sure the 'B' heads came off a '66 442. Sorry to hijack thread. My suggestion: put the A heads on the 455 block and sell everything you don't need. There will be takers for the 425 black and crank. The 'J' heads you can scrap.

 

I think Rocket racing has .921 lifters available!

 

Not everyone. I am thinking that the 425 with a bit less bottom end torque than the 455 would help launching and extend tread life a bit. My thoughts are build the 425 with emphasis on higher RPM power and not have a billion Ft-Lbs torque off the line.

 

I checked. My 425 stamped id on the rt side A head is N-181448.
Before I heard about the larger lifters and the different degrees, I bought my rebuild kit from Northern Auto. http://www.northernautoparts.com/ProductDetail.cfm?ProductId=3030
It is listed for 65-67 425 except Toro. Included cam and lifters.
This is why I assumed only the Toro engine was different.100_0521.jpg

 

An N prefix with no suffix denotes a 1965 4bbl 10.25:1 425.

- Eric

 

Stock to stock the 425 being a 65' will have more horse and torque then the 76' 455. My goal is to rebuild the 425 around stock (470-480 tq). I am thinking of doing a overhaul on the engine and some work on the heads. Anything else I would need to do?