I heard you can only use the LT4 hotcam in 1986 and newer small blocks, is this true?

 

You can use it in any Small-Block-Chevy only if you have Roller Tappets. All Small-Block-Chevys became roller in 1987. 1986-below are all flat-tappet. So in theory, no you can't just slide a cam into the 86-below small-blocks, you would have to machine the block to accept roller lifters, than shell out a few hundred bucks for the lifters. Get a nice hydraulic flat-tappet cam if you have an 86-below small-block. If you have an 87-up, then get the LT4 Hot Cam, it is an excellent cam. Hope that cleared anything up.

-ws6formula-

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1989 Pontiac Formula WS6
69,000 miles.
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305 TBI, 4.10 gears, SLP Zexel/Torsen Limited Slip Differential, 700r4 B&M TransPak, LT4 Hot Cam/Valvesprings, GM Aluminum Driveshaft, 2700 RPM Stall, Edelbrock Performer RPM intake manifold, Turbocity TB. Ran on 6-19-2001 again: UPDATED: 14.1 @ 97.68 mph. Dyno'd Bone Stock @ 172.6 rwhp, 266 ft-lbs. of rw-torque.

 

Oh, yeah not to mention a stronger valvetrain. I'm guessing you have a 86-below 305, right? If so, spend the extra dollars and get the valvesprings and retainers, it can handle much more lift than stock springs.

-ws6formula-

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1989 Pontiac Formula WS6
69,000 miles.
------------------------
305 TBI, 4.10 gears, SLP Zexel/Torsen Limited Slip Differential, 700r4 B&M TransPak, LT4 Hot Cam/Valvesprings, GM Aluminum Driveshaft, 2700 RPM Stall, Edelbrock Performer RPM intake manifold, Turbocity TB. Ran on 6-19-2001 again: UPDATED: 14.1 @ 97.68 mph. Dyno'd Bone Stock @ 172.6 rwhp, 266 ft-lbs. of rw-torque.

 

You don't have to machine anything to put a roller cam in an early small block. Before the factory hipped up to rollers and then took a left turn down a dirt road with their bizarre and expensive and goofy retaining system, the rest of us had been using them for decades.

All you have to do is use what are now referred to as "retrofit" roller lifters, and a cam button. Roller lifters are taller than flats so you'll need some different length pushrods. Of course that particular cam is big enough that you'll probably need new (larger diameter) valve springs, screw-in studs, etc. if you want the motor to last for a long time.

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