No real quedtion or concern here but I ran my engine after a minor refresh and cam, timing set, head swap from #8's to #7's i just did. About half of my original pushrods seem too short (rockers loose at tdc compression) . Maybe because of the felpro head gaskets. I just ordered a set of 8.300 pushrods. $300 Canadian to my door. Holy heck.
I considered doing the adjustable rockers kit I see on line, but it comes with 8.5 pushrods and i read reviews that say they are too long.

Anyhow... the good news: the clouds of steam on first start that had me nearly ripping the heads back off, seem to have been coolant I dumped in the exhaust during disassembly. Lol. I couldn't believe how much steam there was.

 

New cam you say? Could be because of the tad thicker gaskets, but also a smaller base circle on the cam. Most aftermarket cams have a smaller base circle so to make up for that, you would need a slightly longer pushrod. Also, sometimes there's shims under the rocker stanchions when fine tuning lifter compression and if there are, maybe get rid of those to shorten that distance. Of course, you would know if you put them on, so there's that. Not usually used, but still.

Rather than "guessing", which you may be doing with your 8.3 pushrods, you probably should have got a pushrod checker to ensure you got the exact length you need. Of course, there's a little leeway with Olds pushrods, but you don't want them too long just like you don't want them too short. The 8.3's may work for you, who knows until you try them. Ensure you get the right lifter preload.

Something like this:
https://www.ebay.com/itm/254426134815

 

Even with my heads cut to 64cc and my blocked decked .016", I ran into the same thing. I replaced rockers, they do wear. It made it slightly better but still had some ticking. As said, get an adjustable push rod to make sure you have enough preload or the lifters don't bottom out. I trimmed the bridges, trial and error till any movement went away at the rocker arms. It must be the smaller base cams. I have a full roller cam set up, didn't want to invest even more money into this setup. Our Canadian dollars don't go far, across the border. Still waiting on the 68cc Edelbrock heads, will see if they get released to run will my roller cam setup.

 

The new head gaskets, yes, are .024" thicker than the factory so the factor of whether the old #8 heads were the same thickness than the #7s would determine the distance between the rocker cup and the lifter. As you now know, an inexpensive roller tip rocker "kit" may have resolved this with guideplates and studs and given a little more performance but solved the headache of the different additional pushrods.

 

Could you suggest which kit please.

 

Com Cams 1442-kit has everything. Another suggestion would be to use a pedestal mount rocker. Small block Ford (302 and 351 WINDSOR) pedestal mount roller rockers also fit Oldsmobile and would reuse your old pushrods. Just replace the rockers and shim accordingly for lash. Proform brand would be find to use on lighter spring pressures and inexpensive.

 

Waiting 3 weeks for the comp kit. Vendor shipper tracking finally shows movement... shows they handed it off to Canada Post Thursday. On Friday, Canada Post went on strike. This job is cursed. lol

Oh well, quite the test of my cooling system.. I forgot I pumped up the tester to 10 psi and left it on there. 3 weeks later it's still holding.

 

I just noticed the part number I gave is for a 455. The 1441 KIT is for the 350. The difference is the pushrod length. big blocks are an inch taller.

If you did not notice the description and ordered the 455 kit, I would call the vendor or even comp and see if they'll swap pushrods since everything is new.

https://www.summitracing.com/parts/c...ake/oldsmobile

 

I caught that and ordered the correct kit for my 350. Thanks!