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flat tappet cam in a roller block/electric pump

Posted By: mikeasis

flat tappet cam in a roller block/electric pump - 12/03/15 11:39 PM

Can i run a flat tappet cam and lifters in a block that came with roller lifters from the factory? would there be a push rod change if so? And what kind of luck have you had with running an electric fuel pump for a carbed engine?

I found a crack in the block of my 86 4.3V6 after i paid a machinist to flux it, already bought the parts and cant find a replacement block. The machinist is willing to give me a later model roller block and the fuel pump boss is not drilled for the pump shaft.

chair
Posted By: TEAM32

Re: flat tappet cam in a roller block/electric pump - 12/04/15 01:05 AM

You should be able to if you use your original flat tappet cam/lifters/pushrods. The roller motor lifters are longer and require a shorter pushrod. Also, the timing set gears and chain will have to be used from the flat tappet motor, as the roller motor has a retainer plate and the front of the cam is stepped. You would just remove the retainer and install the flat tappet gear and chain. As far as the electric fuel pump goes your car should have one in the tank from the factory for the TBI, so I am assuming you later installed a carb? If that is the case you will probably have to get a lower output pump or you might be able to get a regulator to work to dial back the pressure and or volume.
Posted By: FinallySS

Re: flat tappet cam in a roller block/electric pump - 12/04/15 06:16 AM

Not sure what kind of carb you're running, but for piece of mind, run Pressure regulator.
Posted By: mikeasis

Re: flat tappet cam in a roller block/electric pump - 12/04/15 10:54 AM

yea i have been using an old holley 450 "economaster"

i would have thought these blocks to be a dime a dozen not as one vendor stated rare. The 4.3 was the pig they experimented on i guess.
Posted By: Joe87monteSS

Re: flat tappet cam in a roller block/electric pump - 12/04/15 03:01 PM

If he were a good machinist/shop, he could drill that fuel pump hole, and the oil drainback hole.

You can save some money and drill the oil hole yourself before the block is cleaned.
Posted By: mikeasis

Re: flat tappet cam in a roller block/electric pump - 12/04/15 08:59 PM

heck if he was good he would have caught the crack in the block!
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