petec

I've been out of playing with cars for a few years and am working on my Mustang again. I have a 1971 351W block and I see a lot of talk about roller conversions with conflicting opinions. I have seen people state that you can use the OEM lifters and spider in a 302 or 351 if you run a reduced base circle cam and have also seen peple state that you need the aftermarket roller conversions as the OEM stuff won't work.

I know that when the 302 came out with roller lifters the lifter bores were made taller to accomodate the longer lifter and if you tried to run the OEM cam and lifters in a non-roller block the result was lost oil pressure. Does the same hold true for the 351? Are the bores longer on the roller 351s?

I happen to have a set of OEM lifters and spider sitting on the shelf from years gone by (I used to do quite a bit of engine work) and was wondering if a reduced base circle cam will be the quick way to get my old 351 rollerized.

Figuered it is better to ask those who have been playing with this stuff than built it just to tear it down again. I don't have the spare time I used to have.

Matt Paul

Ive been through what you are going through now.What happens is that the lifter sits down inthe borebuy .030 thousand and the oil holes are block off by the lifter, except when it starts to come up on lift the oil holes line up with lifter and oil flows through.You should only experiance this if you cam has a lobe lift greater then .400 thousands on small base circle.If you still have problems you will have to nicktheside of the lifter on each side that that oil band is around, and oil will flow through no matter where the lifter is postioned in the bore.

Thanks Matt Paul

petec

If I follow you correctly, I need a reduced base circle cam to use the OEM lifters. And if I still have oiling issues to nick the lifter where the oil gallery holes are in the block to keep the oil flowing when the lifter is on the heel of the cam lobe.

danltr450

I always wondered the same thing. I was told by my local speed shop that I dont need a special cam, just a normal roller cam for a 5.0 and retro the block for the spider and stock lifters. I wonder if I was told wrong???

petec

When the roller 5.0 came out a bunch of guys I know ran down to the local Ford dealer to get the cam and lifters to put in their small blocks. The parts guy told them the block was different and a few months later there were tech questions in the car magazines about it stating the either get a new block witht the taller lifter bores or get asmall base circle cam cutom ground.

I wound up putting a mechanical roller in a guys small block and wond up with the spider and lifters I have now. I really would like to find a definitive answer to this as a hydralic roller setup in my 351 would be killer and I need a new cam anyway. If a small base circle is what I need, no problem.

Matt Paul

Its hard to explain andI allready assemblied my motorso a good pic is hard to get.

danltr450

I called the ford performance parts tech line and asked them the same question. i was told by them that I need a reduced base circle cam to use stock style lifters. needless to say, I returned my F-cam to them yesterday and ordered a comp thunder retro cam. those are reduced base circle cams and will work with my lifters that already paid for .

petec

That is the info I needed. Saves me quite a few bucks on retro lifters.