one piece rear seal question

[414banger]

hey guy i have a 350 bored 60 over was going to build a 388 steal block but my engine builder said the one piece rear main seal would not work for a race engine has any body else heard this and if so could i use the 1 to 2 piece main seal adapter thanks for any info

[usafracer]

You can use it you just have to keep all the parts matched up. The one piece rear mains were external balanced.

[powerslide]

the crates are one piece rear seal so parts are starting to get more available

[414banger]

so in your opinion would it be better to build it or try to get the money from the machine work back out of it and save for something else this is going to be a limited late so i was thinking of a 604 crate just to get some seat time then going big for the next season

[dirty white boy]

604 a one piece seal as well as 602,..nothing wrong with them,...just lot more parts available for 2 pc seal...but there's a plenty for the one piece deal too just lil deffernt!!

[dynoman14]

To build a legal 604 the block has to be an 880 casting with 4b-mains.

Right off the bat it will not be legal as the bore size is limited to .008" over.

Just for running local I guess it would be fine.

I have seen those blocks used as high HP as a limited engine in the 625hp range. Performance cranks are available from a couple good sources and are easily internally balanced as any other crank. You will have to deal with the new style cams and lifters but retro kits are out there.

If you are looking to do an "outlaw crate" I have lots of customers making 500-600HP with the original stock crate parts. You need to improve on the rods and pistons which is cheap and get a better hydraulic roller camshaft and lifters, but once you get that done you can turn the engine 7500rpm all day long. I have most of the stuff on the shelf if you can't find it elsewhere. Prolly cost about $2500 for the kit to get it done ( cam, lifters, springs, retainers and locks, rods, pistons & rings, ). That will get you to about 500hp level, getting above that requires some head work and that runs about $1750 for new valves, valve job and port work.

Outlaw crates are not legal for sanctioned GM Crate competition and do not come with crate bolts or seals. I developed my "outlaw" engine just to see how much power I could make with the GM 604 crate package.

[414banger]

thanks dynoman14 i am not required to run a crate motor i was just looking at cost and trying to get some seat time i am leaning toward just setting on it for awhile and save and buy a motor complete at the end of year