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Mixing and matching Big Block 454 parts

mtnman210

mtnman210

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I've had a torn apart 454 I've been planning to put in the project. I wanted to build it into a fun motor. I plan on doing a complete build from the bare block up. Now I have a dilemma. The crank is bad on my current one but I believe that's the only major problem.

Today I got a sweet donor motor that I planned on pulling the crank from and doing whatever with the rest. But I ran the numbers on the block and came to a question:

My current motor is marked
3999289....454.......71-79...2 or 4 bolt, some "CE" replacement blocks had four bolt main caps---mine is the 2bolt main
and has 049 heads on it.

the donor motor is marked
10237297...454.......96-up...4-bolt, Vortec 7400", "L-29" Gen.VI
and I don't know what heads yet.


Now I'd rather run the 4bolt block if possible but I don't want the Vortec heads. The motor is listed with vortec heads so my question is if I were to run the newer block can I use my 049 heads even though the block is listed as a Vortec block?


Also will I be able to use the Crank form the donor in my current older motor if I end up running the older one?
 
should be fine they are still the same till the 502 i belive, correct me if im wrong.but all are the same except that motor
 
The cranks will not interchange as the butt ends are different (old = 2pc seal / new = 1 pc seal).

I believe the Gen 6 motors (4 bolt block) had coolant passage changes to allow Gen 4 heads (049 heads) to work.
 
You cannot put Gen IV heads on the Gen V or Gen VI block without doing a whole bunch or coolant passage work. There is nothing wrong with the Vortec heads, in fact they'll flow much better than the "049" heads. The only downside to the vortec heads is the fact that the valve train is non adjustable in factory form. Comp Cams makes a retro-fit kit to make them adjustable though.
 
well this sucks then I'm in pretty much the same spot I was in. The Gen VI heads look like they will need a lot of work and have some rust in the passage ways. But the 049 heads are in great shape.

And the cranks not being interchangeable kinda sucks. Is there anyway or conversion that can be made to run the different style?

I'm hoping I'll get to tear the Gen VI down this weekend and see what the internals are like.
 
If memory serves me right, you can use those parts. For one, the Vortecs are not better than the 049s. The 049 are one of the best "junkyard" head for the street. Junkyard meaning you could get one out of there, not talking aftermarket. I had a 454 built for my car years ago. I had a steel 427 crank, and wanted to buy a bare 502 block. Guy told me there is a kit that converts the block to 2-piece over the 1 peice. If they have it for one style, should have it for the other style as well..

Same for the heads. I had a set of alum Bowtie heads on my 468. Says it will fit the newer motors, but have to use a specific head gasket, as it covers up any passages not being used.
 
FYI, you don't need 4 bolt inless your gonna be running crazy RPMs or maintaining them for a long period, like in a boat.

The motor that had made 550 horse, had it to 7k ONCE and was fine. Talked to various engine builders, all of them said for a street car, it would be fine. Never had a problem with the motor, wish I would have kept it.....
 
a 2 bolt is more than strong enough for any street car or offroad vehicle, so doint worry about that.

whatever way you go, have the assembly balanced.
 
b454rat said:
If memory serves me right, you can use those parts. For one, the Vortecs are not better than the 049s. The 049 are one of the best "junkyard" head for the street. Junkyard meaning you could get one out of there, not talking aftermarket. I had a 454 built for my car years ago. I had a steel 427 crank, and wanted to buy a bare 502 block. Guy told me there is a kit that converts the block to 2-piece over the 1 peice. If they have it for one style, should have it for the other style as well..

Same for the heads. I had a set of alum Bowtie heads on my 468. Says it will fit the newer motors, but have to use a specific head gasket, as it covers up any passages not being used.
Click to expand...

Well since you seem to be the expert about this (even though i've been a professional Automotive machinsit for 21 years now) i'm done in here. I think i'll just reserve my professional advice to those who PM me looking for it. :rolleyes:
 
mtnman210 said:
well this sucks then I'm in pretty much the same spot I was in. The Gen VI heads look like they will need a lot of work and have some rust in the passage ways. But the 049 heads are in great shape.

And the cranks not being interchangeable kinda sucks. Is there anyway or conversion that can be made to run the different style?

I'm hoping I'll get to tear the Gen VI down this weekend and see what the internals are like.
Click to expand...


So I take it this Gen VI block was the "FREEBIE" you were bragging about earlier??? :eek1:

I can sympathize. The killer deal usually has a dark side. My "runner" 454 core for $500 ended up being a "3-spun bearings, wasted crank" 454....

Anything big-block Chevy is bound to get expensive in a hurry.



Oh, and I'd listen closely to 4X4HIGH.... and take a look at his previous posts on this site. His advice comes from a vast amount of personal engine building experience.


:usaflag:
 
Greg72 said:
Oh, and I'd listen closely to 4X4HIGH.... and take a look at his previous posts on this site. His advice comes from a vast amount of personal engine building experience.


:usaflag:
Click to expand...


Greg, you're a little biased since i've built 3 of them for you already. :haha:
 
I just want to chime in to say anyone that dismisses Scott's advice or knowledge here is truly a fool and deserves to find it all out the hard way (read expensive way)

I haven't had Scott build me anything, but have watched him consistantly diagnose and help with probelms in his area of expertise...which is building engines. If I was building a motor Scott would be the first person i talked to before spending the first nickel on anything.

Rene
 
The bore of a 502 block is 4.470" and a 427 crank has a 3.75" stroke so that would make a 470ci engine.

You have to remember though that it would take special pistons to build that combo.
 
why special piston, what special about it? don't reckon i've seen or heard tale of a 470 cid, short stroke big bore,...reminds me of the 327 crank in a 400 block idea..i've been looking for a LJ 327 crank, i'm going to build 1, selling my SJ 327 crank, would like to build it, 4x4high do you have a 283 or 327 SJ block...iirc the 283 was same as 327 block...i've heard there is a sbc thats newer but is 2 piece rear main and had 327 stroke....307?maybe, i want a 400 w/327 crank!
 
blazin_blazer said:
why special piston, what special about it? don't reckon i've seen or heard tale of a 470 cid, short stroke big bore,...reminds me of the 327 crank in a 400 block idea..i've been looking for a LJ 327 crank, i'm going to build 1, selling my SJ 327 crank, would like to build it, 4x4high do you have a 283 or 327 SJ block...iirc the 283 was same as 327 block...i've heard there is a sbc thats newer but is 2 piece rear main and had 327 stroke....307?maybe, i want a 400 w/327 crank!
Click to expand...

The reason for the special piston is because the pin height will need to be in a different location because of using a shorter stroke crank.

A 283 has a 3.875" bore with a 3" stroke. A 327 has a 4" bore with a 3.25" stroke. All 283's are small journal and all 327's up to 1967 were small journal then in 1968 the 327's were all large journal which is the same for every other SBC ever made from that year and later.
 
i know a 327 sj block and a LJ 327 crank have been very elusive! once i find my LJ 327 crank, any ideas of rod piston combo, in 5.7 or 6'' rod lengths...thanks for info @ 283 327 being diff, i'd been disappointed if i had bought a 283 block thinking it would fit my sj327

i'm about to eat...then i'm going to take some pics and start a new thread, and i'd appreciate if 4x4hi or someone can id a part, i've never seen a connecting rod w/o balancing pad on big end of rod, but got a set today, i'd like to know about. thanks
 
4" bore and large journal sounds like a regular 350 block. Sounds to me like the only hard part is finding a LJ 327 crank.

Rene
 
yes, finding that crank, is my holdup...i've wanted a 400 w/327 crank for awhile, i will need help finding the correct rod/piston combo. want a 6'' rod for more torque from the longer rods, it should be a good quick revving motor...

mortec says a 307 has a bore/stroke of 307 = 3.875" x 3.25"
a 327 has bore/stroke of 327 = 4.000" x 3.25", would a 307 crank work in place of LJ 327 crank in my 400 block? 307's seem more plentiful than LJ327's...will a 307 crank go in a 350 block to build a 327 w/o having to locate parts thats like hens teeth to find?
 
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