some newbie sbc questions


New Member
May 17, 2022
I am new to sbc's so please be gentle....I'll have more ?'s as I move a long with this.

I have a roller 350 out of an '87 Iroc Camaro originally a TPI engine. It was an automatic trans car and I plan on putting in a second gen Firebird with a manual trans.

Will I need to give the machine shop the flywheel I plan to use and the harmonic balancer or can I just add them later after the rebuild is complete?

Is this year sbc internally balanced?

Will this '87 block accept the pivot ball stud for the bellcrank the 2nd gen F-bird uses? I thought I saw the hole near the oil filter but I didn't look to see if it was tapped.

Is the back of the crank drilled to accept a pilot bushing since it was originally in an auto trans car?

Is the OEM roller cam in this engine considered a billet core? If so, which fuel pump push rod is correct for it? The 3704817 rod?


Veteran Member
Jun 17, 2006
Yes you should inc. the balancer and flywheel when balancing a rotating assy. as that's what my engine guy asks for. I do think the '87 and up engines were externally balanced. Cut off was the end of '86 but I could be wrong on that one.


Veteran Member
Oct 15, 2009
Peoria, Az
I believe they had a neutral balance harmonic balancer but a weighted flywheel. The roller cam is not a billet core and is likely a turd of a camshaft. There are tons out there that will work that aren't super expensive especially if you already have the lifters and dogbones/spider hold down parts. And I do believe the crank will accept a pilot bearing. I used one of these blocks and put a two piece seal crank with adapter and a decent Howards cam. Turned out pretty good.


Veteran Member
Oct 9, 2020
3704817 fp rod is correct for either GM cast iron core or GM billet steel core.
Afaik, all GM rollers are on a billet steel core; both OE series production and crate motors. Well-made, regardless of profile.

If it were mine, I'd provide the balance shop with both damper & flywheel I expect to use. OE production One-piece rear main seal sbc are a "hybrid" in that its damper is neutral while its flywheel is weighted. And, of course, the bolt circle/pattern on 1-pc rms motors is smaller than bc of 2-pc rms; No interchange.

BTW, if the aft-end of 1-pc rms crank (upon which rear main seal rides) is worn with a groove, it must be addressed. A good SOP solution is a very thin stainless sleeve which easily presses into place. Cheap, reliable & offered by several hard parts manufacturers. "redi-sleeve" "speedy-sleeve" etc. Quite similarly, a worn damper snout can also be sleeved. But if damper has much age and if its rubber has seen lotsa hot oil, the rubber is degraded and damper replacement may be prudent

.A set of 16 North American-made (e.g. Elgin mexico) OE replacement hyd roller lifters can be had for about $100. I'd replace lifters w/ new but first ensure the motor is not a 305.


Keeping the sound of Cammed V8s alive and well.
Feb 14, 2019
Yes balance all together, if you change damper, balance with new damper not the old one. It's easy to think we'll it's balanced, now I can add new balancer later because it's already balanced.... Works in theory, but not good idea. A lot of times especially when budget it tight..., go ahead balance rotating assembly, then get back from machine shop, finish assembly, do the install, then next month I'll have to $250 to get the balancer... Understandable, and on a basic street car, you can get away with it, but still not good idea.

On cams, the problems were mid 80's Chevy (GM Corporate) 305's mainly and Iron Duke 2.5 4cyl (Fiero). Had several come in on warranty little as 6 months driving time with flat lobes. Fiero's and X-Body Front Wheel Drive were the worst, 305's were next. These cams were hyd flat tappet. Dont recall issues with olds 307.


Keeping the sound of Cammed V8s alive and well.
Feb 14, 2019
$250 ... street sbc / BBC ... why so much for a balancer / damper?
Just an example... point being, get all the parts you intend to use to machine shop and balance all together...

For just tickles and giggles....

#66510 = $82.99
#34262 = $196.99
#620101 = $354.45

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