383 Chevy 5.7 heavy beam rods and cam lobe clearance.

[Bill Chase]

With big heavy 5.7 I beam rods and 3.75 inch stroke.. at what point does lobe to rod clearance become a problem?

.370 lobe lift? Or does lsa, icl, and all that compound it so even lower lift loves could run Into interference problems?

[77cruiser]

What brand of rods? If Scat pro comp or similar profiled rod I'd say no worries.

[Bill Chase]

Heavy beam rods, it's a blueprint shortblock.

[DCal]

I'm about to do the same thing, can anyone remind me which cylinders are the ones most likely to have this interference? Sorry if this sounds like a hijack but its relative.

[rustbucket79]

The height of the cam lobes remain the same unless it is a reduced base circle cam.

A roller cam due to the broad lobe is more likely to have rod clearance issues than a flat tappet cam.

Some rods are designed with more clearance than others.

I’m afraid it’s trial and error in your case, good luck.

[rustbucket79]

1,2,5,6

[DCal]

1,2,5,6

Thank you sir

[BillK]

Bill,
I dont think the beams have anything to do with it. The cam lobes hit the top outside of the rod bolts themselves if they have through bolts. If you can get hold of a stock 400 rod you will see where they are lower for more clearance.

[jred]

also 400 rod bolt is shorter,, I have used scat I beam rods the ones with a through bolt and had to clearance the rods for cam clearance not had much problems with the scat cap screw bolts .. neat trick I saw on clearance to cam is use 4 3/4in wide by as long as you want cardboard and stack them together and put the in between the rod and the cam lobe turn the engine over and see if it hits remove 1 section and check again if it clears your ok,, by the way I use the cardboard that comes in the FELPRO gaskets set it measures about .018 per strip...hope this helps

[Geoff2]

I would think LSA of the cam will affect clearance.

[Bill Chase]

I guess I'll just have to recheck it. I had a 226/286 intake 234/294 exhaust 581/581 112 lsa 108icl with no clearance issues.

I have read multiple times where guys have went to less lift and duration but with more aggressive lobes and had clearance issues.

If I have to pull the oil pan and double check and or clearance a couple of rods so be it.

[77cruiser]

A piece of solder works smashes down & it's easy to measure.