I am planning on rebuilding my 305 soon and its an 86 block with flat tappets. Do I have to do anything to it to put in a roller cam and lifter set, or does it just go in?

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Rob
'86 TA 305 TPI

 

The various cam mfrs. have been making rollers for decades before the factories finally caught on. Unfortunately, when Chevrolet decided to step up, their engineers took some kind of real bad drugs the night before the project was due or something, so the factory stuff (unlike everybody else's) requires a block specifically altered to accomodate it.

The original design lifters, now referred to as "retrofit", did not use a "spider" retainer. Instead they have links that join the 2 lifters for each cylinder together, so they can't turn. So much simpler than the factory's hallucination. The original design roller cam simply uses a "button" that has a Torrington thrust bearing in it, that goes between the front of the cam and the timing cover. Again, much simpler than the factory's stuff.

So, you need to buy a "retrofit" camshaft and lifters; the thrust button; and different pushrods, which are about .400" shorter. IIRC the nominal length for SBC pushrods in that system is 7.400" but you may have to experiment to get it perfect. For some applications (notably TPI), you would do well to have one of the late model grinds ground onto the early model style cam blank. Comp, Crane, Lunati, Ultradyne, etc. will all do this for you.

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"So many Mustangs, so little time..."

 

Couldn't have explained it better myself. The only part he left out was the ungodly cost of going to a roller cam setup. Better tell your girlfriend she'll be going dutch on the dates for a while!



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89RS w/350 TPI; 69RS/SS w/450 HP 350/Muncie 4-Speed "Too weird to live, too rare to die."

 

Ever seen the prices for gasket sets for roller, one-piece rear main seal 305's? That difference alone is half the cost of retrofitting a non-roller block with the good roller stuff!

By the way, be sure to change your distributor drive gear as well.

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82 Berlinetta, orig V-6 car, now w/86 LG4/TH700R. 2.73 unlimited slip. Cat-back from '91 GTA, Accel HEI SuperCoil. AMSOIL syn lubes bumper-to-bumper. Daily driver, work-in-progress (LB9 w/ZZ3 cam, TBD heads, exhaust, paint, etc.).
57 Bel Air, my 1st car. 0.030 over 396, Weiand Action+, Edelbrock 1901 Q-Jet, Jacobs Omnipack, 1-3/4" headers, TH400 w/TCI Sat Night Special conv & shift kit, 3.08 10-bolt, AMSOIL syn lubes bumper-to-bumper. Best 15.1 @ 5800' Bandimere. Daily driver while Camaro was being put together.

 

By the time you get around to buying all the new parts to convert an '86 block to roller cam you have near $700 into it. Retro-fit roller lifters go for $300 or more.
Cheaper to find an '87 up roller cam 305 block, a blown motor or somebodies leftovers' from a previous 305>350 project. Your one piece seal crank would go right in a newer block, etc.
You can get used rollers and the other parts off ebay or the classifieds here for pretty resonable. If you weren't in AZ I'd
give you my old '89 305 block for free... it's just sitting outside getting wet.

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'89 Formula - Thunderchicken - 355 Vette L98/T-5/3.45 9-bolt/black/t-tops - the fun car!
'90 GTA - The GTA - 5.0 LB9/TH700/3.27 9-bolt/black/t-tops/tan leather - the cruiser.

 

Yep, I agree; it's an EXPENSIVE proposition.

You'll need camshaft, lifters, springs, pushrods, screw-in studs and guide plates, )mods to the pushrod slots in the heads if you're running iron heads), thrust bumper and 3 piece Torrington bearing set, gaskets and fluids and plenty of labor time.

To do it 'right', you'll also need all the tools required to degree it in - positive stop indicator, pointer, degree wheel, dial indicator and magnetic base.

I made the swap last year and if it hadn't been for the fact that I got the ZZ9 and lifters for a 'song' I could not have justified the cost; considering my four kids with one in college.

I figure you'll be over $1,000 in parts even if you do most of the labor yourself.

The cam and lifters with be about $700 (ZZ9 prices), springs will run another $100/$125 or so (plus installation if you don't have the equipment to swap them yourself); pushrods will run $80 or so; you'll need screw-in studs and guide plates and machine shop work if your heads aren't already set up wih them. Roller rockers are desirable, but not absolutely necessary with some grinds. Mods to the inside of the valve cover oil drippers if you opt for roller rockers.

It's a big move but worth it if your budget can stand it. Otherwise opt for one of CompCams Xtreme Energy hydraulic, flat tappet cams, lifters and springs.

Jake

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1986 Corvette Coupe, 415 CID, Edelbrock 6073s, ZZ9