[sune]

Hi

As some of you might have picked up I just wasted my 454 big block.

I have been thinking about getting a new rotating ***. with a .250 increase in stroke. But do I really need all the high dollar forged parts or will the cast one do fine.

It is all going in a camaro from 68. it is not a race car but I do drive it hard on the weekends and it sees an occasional trip to the strip. I plan to keep the rpms under 6000.

I have been looking a lot at this site their prices seem good. http://www.fastengineparts.com/index.php

btw. I'm shooting for about 420 - 520 hp. not more because then I'll have to upgrade transmission rearend and so on.

Sune

 

[ponykiller511]

forged

Do you plan on using nitrous ?

 

[badazz81z28]

I dont think you will need a forged crank.
Aftermarket cast cranks like scat are rated at 700hp. I would reccomend forged pistons. Just incase down the road you want nitrous and to save you if you have some detonation. But if your on a budget get hyperutectic. 4340 rods I would say is a must.

 

[GoneNova/406]

i think you'll find that's more of an individual preference.scat 9000 series is rated to 600 for the small block anyway and eagle for the same price is rated at 500.i just got the eagle myself and cause i wanted to but i feel safe with it to 500.if not jegs will work with me.i was going to trust the stock crank that far.if i had the money right now and could afford it though ,there's nothing like feeling the safe assurace of a steel crank.even a 5140.

 

[ChevelleSS_LS6]

I'd have the cast crank balanced, get excess casting material off the rods, and go with forged pistons. Take the heaviest piston and the lightest rod, and vise-versa to make the whole assembly as balanced as possible.

I don't know alot, so there's no gurantees. How right am I?

 

[ponykiller511]

True.....If you are building a mild motor, no nitrous and under 6000rpm. 9000 series Scat crank, 4340 Scat rods and a forged Speed Pro piston would be great. You would stil be able to use a little NOS (100-150) If you want. Balance is very critical........
I just finished an engine using a Scat 4340 crank. I purchased the 9000 series first, but it would have needed 4 slugs of heavy metal to balance. The 4340 needed none. At 50-60 bucks a pop for slugs I spent the same money for the forged. If I wouldn't have balanced the assembly I would have never known.

 

[Siggy_Freud]

Nothing like safety and assurance. However for smaller nitrous shots (75-125) the adverse affects can be countered by increasing the fuel/running a timing retard controller. This makes it so its not a nessesity to run forged pistons/rods etc.

Keeping it within the expected HP figures seems reasonable for cast equipment.

 

[Robinson Robin]

In my opinion high dollar forged cranks and pistons are used unnecessarily far to obtain on the street and some times come with their own set of disadvantages not to mention price. The bbc cast crank should handle the hp you are looking at and together with some good hyperutetic pistons and good rod bolts you should have a durable and affordable powerplant.

 

[ponykiller511]

you can get a 4340 4.25 stroke crank for less than $600.00. If you are going to use a 4.00 stroke a stock cast crank should work fine. but a 4.25 stroke forged will only be $100 or so more by the time you balance it. Even using a 502 flywheel with a heavier counter weight didn't help. (yes it will fit a 2 piece main crank) Brian @ SCAT recommended this but it didn't work.
ALL of these guys are correct, If you use the stock stroke a cast crank will be fine for 450-500 hp. Good rod bolts, The Scats use a cap screw and may be less than rod bolts and resizing. Pistons are a toss up. hyperutectic would work fine. If you think you will use nitrous the forged would be good insurance. Adding fuel and pulling timing is a no brainer, but you never know................................:evil:

 

[Siggy_Freud]

Youd be suprised at the amount of people not readjusting for nitrous then the going forth to tell all about the dangers and damages of nitrous. Like most things . . . small doses and smart minds and things will work okay.

In any case though . . . pony is right. A little insurance will bring peace of mind.

 

[sune]

Thanks for all the informative replies!

I will not be running any kind of power adder or nitros on this engine.

so it seems that the general opinion is cast crank and rods with forged or hyperutectic pistons. If I get the whole assembly balanced? I'll then have to get a new balancer and flexplate right? because the ones I have are externally balanced.



sune

 

[ponykiller511]

You can use your current balancer and flexplate. As long as you have the assembly balanced with your components you will be fine. Internal balance would be nice, but it can be more expensive and in your case unnecessary.:thumbup:

 

[sune]

okay that is god news as they are almost new.

sune