first off my block is a 73 350 flat tappet block. and i can get a roller setup from my friends blown 305.

couldnt find the question being raised here (but im sure it has been before)

If I were to get my hands on a roller block's spider lifter hold down and the dogbones, drill and tap the three holes needed, buy the pushrods, lifters, and whatnot, could i run a roller cam or is there something thats restricting this idea. like different size holes, or metal thicknesses?

i dont want to spend $400 on retro lifters if i can do this myself

 

The only problem I see is the flats machined on the roller blocks for the dogbones.Long time since I looked at a non roller block to remember what the top of the lifter bores look like.
Also need a cam button as no provision for the OE cam retaining plate at front of block.

 

Your 73 block doesn't have the bosses in the lifter valley for the spider. You can't run that setup on a non-roller block.
You can run a roller cam with a cam button and retro-fit lifters (which are much more expensive).

Dave

 

There have been one or two people that have done it. Like mentioned, there aren't bosses there, so you have to drill right down into the main oil galleys. So you really want to make sure it's sealed, or else you have a catastrophic internal oil leak...

Doing this to run a friends used STOCK roller gear is a bit of a waste. A flat tappet cam isn't that bad, grab yourself the right one and use that. or make sure you're very good at fabrication before you convert your block.

 

im not using much stock gear, just the hold down and dogbones to make things cheaper. i would be sure to seal everything. i would be buying a much bigger cam in the .550 range. just asking if it were possible, and what to expect to buy. im good with tools and am willing to take on a challenge. also if things go wrong, i have a few extra blocks lying around.

i know that i can run retro-fit rollers, but as i said, i dont want to throw $400 at the lifters alone if i can just drill some holes.

 

This subject is highly taboo. Anything is possible, just be very very careful. If it were me, i'd try it, just an IMHO.

Do a search for more information. Try "drilling block for roller lifters" or something. I know there was one guy who did it, and he epoxied the studs in place. The block cracked, and the engine failed catastrophically IIRC. I think there's more to the story then that, but he sure got a lot of "I told you so's".

If it were me, i'd drill, make sure it DID go into the main galleys (just so there is enough thread in there), then tap it, put in my ready rod, put a nut on, and braze it down to the block. Something along those lines. Braze, not weld, not epoxy.

Good luck, post up if you do it.

 

ok, what if i didnt drill into the oil galley and i just tapped 8 holes to just bolt the dogbones down?

i think that sounds like a safer way of doing this.

is there any reason not to?
something im forgetting? as im not looking at a lifter valley while thinking.

 

Where are you going to drill the holes?

 

between the lifters.

 

I've never heard of that... How would you bolt down the dog bones? Paint us a picture here....

 

If you are set on a roller cam ,sell / swap the block and get one from a 350 Vortec from a 96-00 pickup.
Common as and takes all OE roller parts.

 

drill a hole in both the dogbones and the block between the lifters tap the hole in the block and bolt it down. i know its harder than it sounds, but everything is. is there anything through that part of the block, or just iron until the cam?

it would be a pain, id need a new rotating assembly or bore it out because my block is bored .060 over as is.

 

The lifter oil galleys are under there.

 

i have all good roller parts that i will sell u from my 98 vortec motor