Clear up some conflicting 351 info...

[seijirou]

Well I've been trolling around digging up info on that loved topic of 351 swaps, and I'm getting some somewhat conflicting info on changing a non-roller block to roller.
Everybody agrees to drill holes for the spider and do some grinding so the dogbones sit flush and you can then use stock 302 roller lifters, but then some "articles" go on to say you then run a reduced base circle cam, and others make no mention of this whatsoever.
So from someone who has done this before, what's the deal? Can a person do the block modifications and run a stock 5.0 mustang camshaft, or do you need to get a special cam in addition to the block modifications.

oh side note, I pulled a 351 out of a 93 van two days ago, the original engine, not a roller block, BUT, it was ready to be roller from the factory, the holes for the spider were there and threaded, and the area around the lifter bores were flat. Shame my block is an 88.

 

[R2D2]

small base circle cams can wreak havoc on valvetrain at high rpm and the very limited selection of them is alone enough to save some pennies, run a solid roller of a solid flat. People are just too lazy to lash valves every once in awhile, thus they choose the hydraulic roller. Depending on build quality and parts selection along with the cam, one can find 20+hp running a solid roller. One of my clevelands runs a solid flat and makes 680 at the crank, very mild motor on pump gas. Solids have been powering some very stout combinations for decades

 

[seijirou]

small base circle cams can wreak havoc on valvetrain at high rpm and the very limited selection of them is alone enough to save some pennies, run a solid roller of a solid flat. People are just too lazy to lash valves every once in awhile, thus they choose the hydraulic roller. Depending on build quality and parts selection along with the cam, one can find 20+hp running a solid roller. One of my clevelands runs a solid flat and makes 680 at the crank, very mild motor on pump gas. Solids have been powering some very stout combinations for decades

The question remains however, if I convert this 351 block from flat to roller, can I use a normal base circle cam. Knowing that I don't want to run a reduced base circle cam, I'm not going to convert my block if that means I must use a reduced base circle cam. That's the one question about the swap that I havn't been able to get a straight answer to.
Has anybody here converted a flat lifter 351 to roller lifters and _not_ used a reduced base circle cam?

 

[vristang]

I wish I knew the answer, but my only suggestion is to call the cam companies and let them sort it out. This is what I did with mine.

I am pretty sure that the cam I have is a standard 302 base circle.

The base circle debate seems to focus around the lifters that are used.
For reference I am using standard 302 roller lifters.

I hope this thread gets some serious responses, as this is a very good point to clarify.

jason

 

[seijirou]

Jason,

I just may end up calling the cam companies about, solid suggestion, thanks