454 build question

[Nukem]

So i recently acquired a 1984 Monte from a family member. Currently no motor or transmission and I am looking to make a hotrod out of her. 600 streetable hp is the goal. Along with the car i received a virgin 454 block a new 396 forged gm crank (3.760") and a new set of keith black flat top forged pistons (also 454) my question is what connecting rod length can i use to get in the correct compression range (11-12:1) to make this combo work efficiently?

I hate to have a $700 crank or a $500 set of pistons on the shelf and not be able to use them for this project. The easy answer is go buy a set of 427 pistons i guess but i am trying to avoid that.

Any advice would be appreciated!

 

[MrSony]

Nothing with 11:1+ higher compression is gonna be streetable. I'd shoot for 10.5:1 and less. There are plenty of builds out there making that number with lower compression. On the other hand, if you have the cash for 100 octane, then go for it.

 

[Nukem]

Nothing with 11:1+ higher compression is gonna be streetable. I'd shoot for 10.5:1 and less. There are plenty of builds out there making that number with lower compression. On the other hand, if you have the cash for 100 octane, then go for it.

Rod length for 10.5:1 then?
The problem is 427 is the same bore as 454 BUT the 427 pistons are shorter wristpin centerline to top of piston. What i am trying to find out is what is the difference in height there? And therefore the difference in connecting rod lenght?

 

[pagrunt]

I am thinking that the length of big block rods should be the same regardless of displacement. The compression ratio should come from the pistons & head chambers. How strong of a rod should be what drives what you pick. Check out the to see if the crank is balanced for a 427 build first before using it or sell/trade for a 454 crank. Best to check the cast numbers on all OE parts to make sure they are hi pro parts. Just take your time to see what really got and what you could use to build what you really want.

 

[565bbchevy]

I am not sure what you are attempting to build but I feel if you are shooting for a streetable 600 horsepower you are going to need cubic inches and using a 3.76 stroke crank defeats that purpose by making your 454 a 427, you would be better off selling your crank and getting a 4.25 stroke crank and building a 482-496 with some good flowing heads and a roller cam.
Stock length rods for a 454 are 6.135 but rod length also depends on the compression height of the piston.
What is your 454 a gen 5 or 6 and is it 9.80 deck height?

 

[Nukem]

I am not sure what you are attempting to build but I feel if you are shooting for a streetable 600 horsepower you are going to need cubic inches and using a 3.76 stroke crank defeats that purpose by making your 454 a 427, you would be better off selling your crank and getting a 4.25 stroke crank and building a 482-496 with some good flowing heads and a roller cam.
Stock length rods for a 454 are 6.135 but rod length also depends on the compression height of the piston.
What is your 454 a gen 5 or 6 and is it 9.80 deck height?

It is a 3999289 casting... 2 bolt main 9.8 inch deck height. I didn't want to hear it but i believe you're right 565bbchevy. C.i. is the way to go and the 3.76 crank will not cut it.

 

[565bbchevy]

I personally would do the .060 over and make a 496 with a 4.25 crank, the extra bore size will help unshroud the valves.
Hopefully you are planning on some good heads for this build.

 

[Nukem]

I personally would do the .060 over and make a 496 with a 4.25 crank, the extra bore size will help unshroud the valves.
Hopefully you are planning on some good heads for this build.

Yeah, the intention of using the parts that i have available was to spend good money on a set of heads. Looks like the wallet is about to get thin... Thanks for the help!

 

[565bbchevy]

Without a part number for the pistons I am going to guess that a flattop is probably going to be somewhere around 9 to 1 compression depending on the cc of the heads you choose and I would not be surprised if they are actually Hypereutectic instead of forged since that is typically what KB pistons are know for.

 

[Nukem]

Without a part number for the pistons I am going to guess that a flattop is probably going to be somewhere around 9 to 1 compression depending on the cc of the heads you choose and I would not be surprised if they are actually Hypereutectic instead of forged since that is typically what KB pistons are know for.

KB200 pistons. I reckon i assumed they were forged.... attached spec sheet per the manufacturer who was very helpful btw.