sbc harmonic balancer
 

I have a late model one piece rear seal block and the correct flexplate (externally balanced).

Can I use a small diameter (6 3/8") mid-sixties, low-perf 327,neutral balanced balancer here?

Using an early 80's timing cover, TDC is 10 degrees advanced from the mark on the timing tab, but I'll allow for that. I'm thinking the late model one piece rear seal crank is keyed different.

Allowing for that, is there any reason this hybrid (my term, no one elses. I could use the term bastard, but that's not nice) won't work?

I hate to keep running out and buying stuff when I have it in the shop. Just for a different year.

Call me cheap, or call me frugal. Your call.

Thanks in advance. Adger, I know you could help me.

Re: sbc harmonic balancer
 

I don't know a lot, but I know you can't run a 327 balancer, on an externally balanced engine of any kind.

Re: sbc harmonic balancer
 

yep, it'll work but the timing mark's will be way off UNLESS you use the 327 (or 283) timing cover...or just mak you're own pointer..the 1 piece rear main engines were balanced at the flywheel, not the balancer

400's were a different critter

Re: sbc harmonic balancer
 

OK, didn't know that. Never too old to learn something new.

Re: sbc harmonic balancer
 

Do your engine a favor and put an ATI dampener on it.

Re: sbc harmonic balancer
 

x2

Re: sbc harmonic balancer
 

Back in the 80's we put an aluminum balancer, I guess it was really not a balancer, just a hub that Moroso sold on our 427. It looked nice, it was very light, it was cheap too!
When we put it on the car, it even seemed like it revved up real quick! After it was on the car a few runs, we got tired of picking up all the crap that shook off of the car! It unscrewed almost every meaningful bolt on the car! Even the transmission case cracked!

It made someone a real neat looking ashtray.

Your story made me think of that one we had. Save a little, Spend A Lot! LOL.

Re: sbc harmonic balancer
 

We took the stock balancers off of our 454 based bracket/.90 Super class engines back when NHRA mandated an SFI balancer for 10 second and faster cars. We bought some of those aluminum balance hubs. A few passes later, all those cranks that had a lot of passes with stock balancers were broken, and the timing sets were worn out. We had a rough season that year. The only engine that didn't break was our "high end" (for the time) "big" engine, that had a forged crank and "dimple" rods, and it broke a lot of valvesprings, killed two timing sets, and beat up a set of bearings. That winter, Jim Beattie, owner of ATI, came to the shop (he's a good friend, and has family here), looked at the cars and engines, and asked me how many cranks we broke that season. After he laughed at my answer he told me we were getting some presents for Christmas. A few days later, 4 new ATI Super Dampers arrived at the shop. Never broke another crank, and timing sets started lasting several seasons. We were, and I still am, an ATI dealer, and Jim has always treated me really well.

Re: sbc harmonic balancer
 

Bobby,
In your better terms, yes you can use different parts from SBC's to make them "Hybrids". The late mod crank is keyed the same as the early mod crank as far as I know. the cam timing would be different, too. The number of degrees difference in the mark is in the balancer. I thought it was more than 10 degrees, like 26 for one series balancer and 13 for the other. My memory tells me there are actually 3 different timing combos (locations) for a SBC without the LT-1 and LS. As to the use of the balancer. Yes, you can use it, BUT and that is a big But... It might cause some of the symptoms mentioned in some of the other posts. That balancer you are talking about was designed for the harmonics of the 3" stroke 283 crank and was also used on the low RPM (Low PERF) 307/327's. If this is just a "driver" and not a race car that is going to see some 5,000-7,000 RPM blasts it might survive and your other parts might survive as well. If you want a better stock balancer there is a heavier, extra wide 305 balancer that is about the same diameter as the 6 3/4. I think it will match up to your timing mark, too. That timing mark on your cover is straight down from the top, behind the water pump. You do realize you MUST use a long water pump to see that mark? I think It is about 6 7/8" diameter. From Pioneer they are pretty cheap and I think Powerbond makes a better replacement that is a little higher priced. I know we are talking about a balancer that is NOT Aluminum. How did we get to talking about them? I thought everyone knew the aluminum weren't even good paper weights or doorstops. OK, ash trays! :~)

Re: sbc harmonic balancer
 

I believe that the balancer that I used on my 305 stocker for years is the one you are refering to. It worked fine for me for 20 years, it is a narrow balancer. It would probably still be on my car, but I believe g/s and faster requires an aftermarket balancer and I put one on.

I always assumed that the rear of a one piece seal 305/350 crank is balanced externally, but the front was not. Is that correct ?