451 low deck budget build

[67MPRFAN]

Okay I have a few parts laying around and looking for some advice

A stock stroke 3.75 440 crank that's already been cut 10/10 , so with that being said having the crank turned down to 400 mains and rods cut to 2.200 journals which rods would be best used 6.700 or 6.800 rods, would the off the shelf Pistons of 1.30 something still work

 

[wyrmrider]

get a rod with the correct big end width for your crank
stock LY rods work with new bolts ]
I side grind then mag then shotpeen but you do not have 2
check the length of your rebuilt rods- it will be slightly shorter than stock
DO NOT LET ANYONE ANGLE GRIND YOUR CAPS a little extra clearance at the parting line is no big deal
putting an angle on the cap puts a major strain on the bolts Direct Connection bolts are SPS and a bargain
figure the close to exact compression height you need and the dome / cup for your heads and compression desired
best to square up the block first and get a real deck height form Crank Cl to deck
so what heads? cc the heads before ordering pistons do not believe advertising

 

[67MPRFAN]

I just have a crank and block laying around right now rods and piston still need to be bought. Really looking for ideas I can do with the crank that's taking up space in my garage

 

[747mopar]

My Charger is running a stroker right now built fairly inexpensive using just what you have although I had a set of 440 rods as well. I had the crank turned to fit the 400 block and used KB Hyp pistons. I did the crank clearance work myself on our lathe, I believe 4 throws had to be cut at 45 degree angles until the machined surface was about 3/8" wide then balanced. Don't let them rape you on the clearance work, it's literally only about 30 minutes worth of work.

12,000 miles on it now and it's been a fun reliable engine.

 

[68GTX4SPEED]

I have just bought a 451 with a cut down 440 crank, standard rods and these pistons https://www.ebay.com/itm/Keith-Blac...ash=item2cc9744bc3:g:D84AAOSwi0xaB4WJ&vxp=mtr

 

[wyrmrider]

great piston especially with open chamber heads
We (and others) helped design that series with then KB chief engineer John Erb
The design was based on some custom pistons designed by TMS Propane Performance and the Speed-O-Motive guys who had been welding up the chambers
If you are using heads with a deck you may have to trim off some of that quench dome unless KB as one without the dome
measure everything to get your quench in the .030-.040 range sometimes you have to use thin or thick gaskets or deck the block, or flycut the pistons tops
the early pistons ended up with too much clearance on the 440's - IDK with a stroker
well worth the extra effort
decide on your heads and we can narrow down the choices
if using open chamber (stock) heads then cc chambers at both ends- sometimes you have to cut on the long axis angle to get them the same- especially if they have been worked on before- lots of builders push them through a sander which never takes the same off each end - so BVVC with 40-50 year old cores= or even new ones

 

[747mopar]

great piston especially with open chamber heads
We (and others) helped design that series with then KB chief engineer John Erb
The design was based on some custom pistons designed by TMS Propane Performance and the Speed-O-Motive guys who had been welding up the chambers
If you are using heads with a deck you may have to trim off some of that quench dome unless KB as one without the dome
measure everything to get your quench in the .030-.040 range sometimes you have to use thin or thick gaskets or deck the block, or flycut the pistons tops
the early pistons ended up with too much clearance on the 440's - IDK with a stroker
well worth the extra effort
decide on your heads and we can narrow down the choices
if using open chamber (stock) heads then cc chambers at both ends- sometimes you have to cut on the long axis angle to get them the same- especially if they have been worked on before- lots of builders push them through a sander which never takes the same off each end - so BVVC with 40-50 year old cores= or even new ones

Should have mentioned that, the shop did mill the pistons on mine.

 

[68GTX4SPEED]

And I will do the same because I'm going with aluminum heads from 440 source, all the dome will be gone.

 

[Garys1969RR]

Get your stock crank main journals turned down to 400 size, and use stock 440 LY rods. Use Hi Strength bolts, and get the rods re sized. If you use the stock KB 215 Pistons, the heads will need to be open chamber. 451s run great when built right. Use good flowing heads. I like around 10.5 to 12 to 1 C Ratio, depending on your altitude. I used dome pistons with 915 heads, and that motor was a screamer! 13 to 1 C Ratio.

 

[67MPRFAN]

I don't have rods so I need to purchase some that's why I was asking about using 6.700 or 6.800 rods with 2.20 journals

 

[wyrmrider]

using chevy rods you have to watch the width
you will no longer be in low budget territory
do not fly cut the pistons till you know exactly what the compression height will be
if the pistons are "down the hole" you may need to keep some of that quench dome even with a wedge chamber head
If you can't find any rods I could ship you some- all side ground and magged- need new bolts and a resize- and they have some surface rust so glass bead or shot peen or even wheelabrate
If you do not have a machine shop handy I could check to see what it would take to get them ready to run here- but most likely less costly in Ohio- however they would be perfect

 

[m79ded]

At that point when you cut the crank for chevy 2.2 rods buy 6.70 chevy rods offset grind the crank and 1.32 pistons. you will make a 470 which is very good. With all that work best to get a Molnar 3.91 crank and corresponding 6.70 rods that have the correct width. Either way you do it it's not very cheap. And cheap is not always the best way to go.

 

[wyrmrider]

are you thinking 440 length or 400 length rods?
I only use 440 LY rods

 

[67MPRFAN]

440 length I thought I seen some rods with 6.70 or 6.76 with the BBC journals is why iI' asking

 

[67MPRFAN]

With the crank being 10/10 I was looking for something to comdatee the smaller size

 

[wyrmrider]

just depends on what you want
$$$ / cu in
you have to turn the mains down to 383 size
as you must be aware there are wide late thrusts and narrow early thrusts
the block may be late but the crank may be early
measure the block to see which main bearing set it takes
if wide talk with your crank guy and see if he can widen the thrust - or use the narrow thrust bearings
if your rod journals are .010 you are good to go as far as using a Mopar LY rod
how much does it cost to offset grind the crank to BBC size and how much are the BBC big end rods AND do the pistons come out with correct (correct is what you want to get) compression and quench
pencil it out

 

[451Mopar]

Has anyone used the 440 source Factory replacement rods #200-1132 $250/set with 7/16" cap screws? That may be an option for this type of 451 build.
http://store.440source.com/Factory-Replacement-Rods/products/139/

 

[not so famous bob]

just depends on what you want
$$$ / cu in
you have to turn the mains down to 383 size
as you must be aware there are wide late thrusts and narrow early thrusts
the block may be late but the crank may be early
measure the block to see which main bearing set it takes
if wide talk with your crank guy and see if he can widen the thrust - or use the narrow thrust bearings
if your rod journals are .010 you are good to go as far as using a Mopar LY rod
how much does it cost to offset grind the crank to BBC size and how much are the BBC big end rods AND do the pistons come out with correct (correct is what you want to get) compression and quench
pencil it out

Chevy rods are always cheaper if buying new ! supply and demand thing ! I myself would go chevy type H beam , unless u have, or going to buy used.!

 

[wyrmrider]

Chevy rods are cheaper only if the width is right and you can come up with a piston that works- OP needs to do the math
he kneads to know his crank Cl to deck height within a couple of thou- not rocket science correct, head cc's then figure piston quench compression height with the dish to get compression correct. several here on this site can walk him through the drill
71/6 bolts- whose bolts and do they have near factory big end/ small end weights? plus figure out how much cost to offset grind the crank
your grinder can vary the offset to dial in the compression height

 

[Sweet5ltr]

At the end of the day, you have to look how much you're saving over buying a complete, balanced, stroker rotating assembly which has no guesswork involved. Is it really worth using a 40-year old crankshaft over new production for the cost in a performance build?