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454 bottom end

2K views 19 replies 10 participants last post by  impala 
#1 ·
Have a 70´s 454 Im going to build. Will be 600hp+ and see 6800rpm. Low budget build except heads heads and valvetrain but already have all the parts for the topend.

2 bolt
Cast crank
Thumb rods

Going to bore block 030.
Should I stud the mains or use the oem bolts?

Polish the crank.

Rebuild the rods or go aftermarket? Scat prostock or Eagle sir.

Forged icon pistons.

Balance the rotating assembly will the stock damper work?

Solid roller.
Afr 305 heads
Rpm intake.
 
#2 ·
600+ hp and 6800 rpm are not "low budget".
Factory main bolts will work but studs if in the budget. Another alternative is to find a set of Dart main bolts that someone took out of a Dart block.
Cast crank is fine.
Scat ProComp rods are good for 800hp...would be my choice.
Icon pistons are excellent.
I would not use the stock damper. A good SFI Powerbond or Pioneer would be a good choice.
I'd go hyd roller but that's just me. Make sure you use a good quality timing set like a Rollmaster. Not a place to skimp.
One thing to remember...the top end will produce the power and rpm...it won't know what the bottom end looks like below the rings. Build the bottom end to handle the power and rpm the top end will make.
 
#4 ·
Only have 2500$ total in the build so far, bought the cam, lifters, bolts, pushrods, intake, heads with rocker arms from a person that needed money very bad.
So pretty low budget for me.

Ok will put studs in it.

Thumbrods is out of the question? ARP bolts and resize?

Scat pro stock is rated 750hp and I can get a set new from same person that sold the top end for very good price.

Will get a good damper and flexplate.


One thing, I'd stud the mains and ensure I had a GREAT windage system for that rpm. Sure it may cost an align hone, but that's no big shakes and the hone wont radically alter centerlines.

Cast crank may be sketchy, but frankly, I've only seen broke forged ones, so...? GM rods are fine.
Will put studs in it, moroso 20408 pan is what I think I will use with a Melling select oil pump.

Doesnt Mark Jones use cast cranks in his 600hp BBC’s?
 
#3 ·
One thing, I'd stud the mains and ensure I had a GREAT windage system for that rpm. Sure it may cost an align hone, but that's no big shakes and the hone wont radically alter centerlines.

Cast crank may be sketchy, but frankly, I've only seen broke forged ones, so...? GM rods are fine.
 
#6 ·
I have had friends in the past use cast cranks for years twisting them to over 7K with big compression on BBC's and never broke any. Same thing with GM rods, they will take a lot of pounding. If my SBC 358 can withstand the punishment of 200hp NOS with a cast crank and GM rods I am sure your BBC will be fine. Just crack check everything, a good balance, studs won't hurt either.
 
#7 ·
A friend of mine builds race engines in his own shop. A several years ago he decided to take all used parts laying around and put together a 427. 2-bolt main block, forged crank and stock rods 3/8" rods. He does a consistent 6.50 on the 1/8 and spins 7,000 without issues.

Thumb rods are stronger than stock rods, and he did not stud the mains. I would stud the mains and use the thumb rods.
 
#10 ·
Good , as you'll want 500+ psi spring on the nose of that thing to rev. Or beehives. I also used Ti retainers on my 427 revver.

Balancers are relatively inexpensive. I ran both a new GMPP and a Powerbond in the 427 ( 7500 rpms) . If it's brand new GMPP, it may be ok. If not, as Scott says. Plus on a 454 the balancer, and flexplate/flywheel are required for a complete balance. They need to stay together if possible, for a while. Go new on both ends, as I did. Don't reuse the balancer unless you know its new, is the point.

PS Mark Jones "mated" the flywheel to the engine. If I break it /replace, the balance will be off, both fore and aft, on two dimensions as he warned me. Also, never asked about the crank steel, although I know it's "******" and not GM. AS is my flywheel, as I didnt know, assumed HAYES was "kosher". it aint, its "******"
 
#17 ·
Never heard of that damper. A GMPD performance should be fine.
Flexplate ok
IMO for mostly street use standard piston ring dimensions would be best. Usually better oil control, longevity. Sure narrow rings are lighter and offer less friction, but the piston travel is the same so wear could be faster. Possibly resulting in loss of compression, oil consumption, sooner rebuilding.
 
#19 ·
Studded 2 bolt, get it align honed (please!!), cast crank is fine (get it reground with a good radius), the previously mentioned Scat rods, proper bearing clearances, and those Icon pistons will live a long, happy life. And, it’ll take a lot more abuse than you’d think. The thumb rods would be fine also, but as BillK pointed out there’s no money savings there.
Built a couple using those same parts and wouldn’t hesitate to do another..
Pioneer balancers are pretty inexpensive, used several over the years with no trouble at all.
 
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