1986-z51

Is the lifter bore the same on the L98 roller block as the L98 Flat tappit block?? My son had a machine shop build a roller motor,car got flooded out from ike.Engine has been sitting on the engine stand for 2 yrs. I want to put it in my 86,An use a flat tappit cam an lifters. Can this be done???

rodj

Lifter bore is the same.
You will need a flat tappet timing set because bolt spacing on roller cam gear is different and longer ( 7.800 ) pushrods to suit the shorter tappets

bwiencek

My question - why go 'backwards' to a flat tappet cam? What's wrong with the cam that is in there? If the cam is "too wild" for your car then it's probably almost a wash or cheaper to put in a milder roller cam than to convert to flat tappet with all the associated hardware (cam, lifters, pushrods, matching valve springs, timing set). Good hyd. rollers can be had for under $250 new and if you find a zz4 take-out cam they can usually be had for $75-100.

JAKE

The inside diameters of the lifter bores are the same but as to the height of the bores, themselves, I don't know. Perhaps someone who does can chime in of that.

It's important to know because of how the lifters would ride in the bores; oil passage alignment, pushrod length and maybe some other factors.

I recall reading in a CompCams article that going "back" (from roller to flat tappet) requires changing everything. The specifics weren't listed but I took it as Comp referring to cam, lifters, pushrods, timing chain set. Rockers should be re-usable though, but that's just a guess.

I agree with the previous poster; wondering about the wisdom of going back to a flat tappet. It always troubles me when someone wants to change something so dramatically; asking "How do I install a LS2 in my 85 Vette?" type of stuff. There are so mant details that have to be 'RIGHT'.

Jake

1986-z51

This motor is just a short block,with no roller lifers an no cam.Its really a cost thing,I can buy a cam an lifters for the price roller lifters. Wont need to round up push rods eather.Have my heads done an i can have a rebuilt motor for 500 bucks.Complaments of my son.

redrose

spring of '87, i put a flat tappet cam/lifters in an '87 vette, the owner insisted on a 'wild' cam and no aftermkt 'big' rollers were available yet...cam+lifters+pushrods+timing set wuz all, no issues while he had the car AFAIK.