L69

Hey everyone I have a few questions and hope you can help me answer them.

1- I am building a 68 455 for one of my 66 cars and was wondering if I can install one of my 400 forged cranks into the block and use stock 455 rods or do I need to use the longer 400/425 rods.

2- The 1966 B heads that I plan on using are engine # N723613 and there is no T at the end indicating from a toronado motor so I am unsure if they are 39 or 45 degree heads. Obviously the 455 block will have a 39 degree lifter bore angle and if the heads are originally 39 degree will it affect the top end. Usually I have B heads with engine # V indicating 442 heads with a 39 degree angle but I am unsure of engine # N first set I have owned.

Any help would be appreciated as I hate to start machining and find out that the heads will not work or I will have to spend more money drilling the push rod holes to be acceptable. Thanks.

2blu442

L69, welcome to the site! I've always been under the impression that early 400 and 425 interchange then late 400 and 455 will interchange. The crank will physically fit, but I think the problems will come when you try to mix the rods/pistons but someone who knows for sure will speak up soon.

John

L69

Thanks John

L69

I am assuming that I would have to use the 400 rods with the 455 pistons I have never done this build but it seems like an interesting destroked 455 to 425 plus the added benefit of the forged crank.

Run to Rund

You can use a 455 block with 425 rods and pistons; it will become a 425. 425/early 400 rods are 7" long and the piston compression height is 1.61". 455 rods are 6.735" and compression ht. is 1.74. Early stroke 3.975", late 4.25". So you see what has to match up for the pistons to give decent compression.

aliensatemybuick

I know a guy who did the reverse, i.e. put a complete 455 reciprocating assembly (crank, rods, pistons) into a 425 block (in his '66 Starfire). Not sure WHY he wanted to do that, though I sure like the idea of doing the opposite.

507OLDS

Installing the 425 crank,rods,pistons,simply makes a 425.However,you can have that 425 crank offset ground to 4.25" stroke,like the 455 crank,and use BBC rods.You can stroke it up to 4.2975" without any issues,to get more stroke & cubes from it.There are a variety of rod lengths for the BBC rods.Then find a piston to match,or have a custome set made.

L69

Thanks Brian that may be an option. Do you have any stock (virgin 455) cranks available. Shipping would be to CT

507OLDS

Yes I do. If you decide to use a 455 crank,you can stroke it up to 4.500". I was able to squeeze 4.550" stroke out of the one in the 507.

L69

how much would you sell a stroked 4.5 and or a standard crank for. Also do you know what shipping would be to ct 06417.

cutlassefi

Just an FYI, you can buy a new Eagle crank for anywhere from about $450.00 to $550.00.

507OLDS

You might have a little less into an Eagle crank,depending on what type of finishing work it will need.I highly doubt you can install it straight from the box,so you need to take the initial cost,plus the cost to finish it,then compare that to buying a nice N-crank,and having it offset ground & finished to your desire.
I can check on shipping,but you will probably have about $200.00 into the crank,once it gets to your door.Then you need to have all the machine work done.I use 2x10 lumber,to make shipping crates for cranks.They weigh about 75-80lbs when packaged.
30" x 12" x 12"

Texas Jim

I think that it's great that you guys are honest w/ your work prices and shipping, and what another brand would run, other options a person has. I see on other sites I frequent that guys are less apt to come off w/ prices or to let a person know about other options they have available to them. Thanks so much f/ being honest and treating one another correctly.

L69

Just to let you guys know I built a customer engine recently 455 destroked with 400 crank and 7" 400 rods, and he is very pleased. Its was sort of an experiment since he had a 455 block and the internals of a 4 speed 400. Motor was dynoed at machine shop making 419hp 488tq. Total displacement was 438 with a .060 overbore in the 455 block. XE274 cam and Toker on top with a 850 carb. Compression was a honest 9.7-1 and it is a nice street motor. These are real numbers and a fairly mild build but he stated he has had her up to 5800 and all held up good and he felt there was plently more. I told him I only warranty my motors to 5800 hehehe, I know he can do 6000 all day long, heck I have had my 400 up to 6500 recently and it was a blast. Please understand these motors have had all proper machining, balancing, proper clearances and HV oil systems. Good luck to all.

64Rocket

How did you get the stock 400 cid rods to fit a de-stroke early 400 crank?

Gene

L69

1.You take a 455 block
2.You take 400/425 7" rods
3.You mount those rods to 425 .060 over pistons from egge
4.You add a 400/425 crank and vuala! You now have a destroked 455, actually a 438, its quite simple

cutlassefi

Really, apparently your math is magic! Vuala! Let's look at this a little closer shall we.

455 block, typically approx. 10.625 deck height
400/425 rods, 7" length
455 pistons, most are approx. 1.735 comp distance
400/425 crank, 3.975 stroke

By my math that equals 10.722. What did you do with the extra .100 hanging out of the top? Did it magically disappear? Vuala!
Hmmmmm. I think somebody ain't tellin the truth.

cutlassefi

But somewhere along the line not proper addition

507OLDS

A +0.060 piston for what engine? Olds,Pontiac,? If you simply transplanted an early 400/425 rotating assembly into a 455 block,you would still need the shorter 425 style pistons.

A stock stroke/stock journal 455 crank,7" 400/425 connecting rods,and 455 Pontiac pistons will work.Been there,done that.Just don't chop the deck down.

64Rocket

Mark, that is what I came up with.

There has to be some info missing.....
maybe the new fuzzie math..

Gene

L69

Ok maybe egge 425 .060 pistons with the shorter comp distance either way no pistons were cut and deck and heads were milled to a near zero deck height. Havent heard a piston hitting a valve so it worked. My mistake if I didnt specify 425 pistons vs 455, def were not ponchos as this had a small dish and not valve relief.

L69

actually according to your match 10.722 minus 10.625 is not .100 its actually .97 so where did you learn your math or did you use a polish calculator, lol

L69

cutlassfi you may cut a good cam, but you are def staying away from my taxes, christ almighty...hehehe

cutlassefi

You did the build and you don't even know what piston you used. I was a helluva lot closer than you!!
And you'd wait to hear a piston hitting a valve before you checked it? Hmmmmm...

L69

well like i said in a previous post that you clearly did not read I DID use 425 pistons and engine was machined for zero clearance so Obviously it must have been checked,duh!!!!

L69

I corrected the post where it states 455 pistons. It now states 425 pistons. Are you happy now?

cutlassefi

Dude, other people read this stuff and take it from there. So if your info is wrong guess what, someone may take that as bible. Especially since you did the build.

Take a minute and read what you've typed before you post it. That's all I'm asking.

Fwiw I don't think you really know what piston you used. Jmo.

64Rocket

Basically you built a 425 w/.060 over 425 cast pistons, using a 455 block.

This way would have been a better way to state what you did.

Gene

cutlassefi

X2. Like I said I'm not sure he knew the real combo.

507OLDS

We have a +0.060 425 Olds.Simple as that.

Run to Rund

voila, x4. lol.
Definition of VOILĄ

—used to call attention, to express satisfaction or approval, or to suggest an appearance as if by magic