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go roller or flat tappet
Posted: Mon Jul 19, 2010 9:02 am
by painterdude923
bought a 1990 5.0 came out of bronco. would it be worth it to drill and tap holes in the block for the spider to make it a roller cammed motor or just go with a nice flat tappet cam?
Re: go roller or flat tappet
Posted: Mon Jul 19, 2010 12:47 pm
by cgrey8
If it were me, I'd be converting the block to take a roller cam.
The main reason is because the cam options available to a roller block are greater just because the Mustang, Cougar, and a few others were HO roller engines.
The other benefit is just getting to run a roller cam which can handle much faster ramp rates with relative ease. Faster ramp rates open the valves faster, hold them open at their optimal flow lifts longer, and get the valves closed back faster. As a result, you can run more street-friendly durations without sacrificing power at the top-end. The only catch is you generally need stronger springs/seat pressures to handle the sharper ramp rates.
If you do the conversion, one thing you should NOT assume is that just because you have a roller cam, that it'll have a fast ramp-rate. Stock roller cams and most all of the FMS aftermarket cams do NOT have fast ramp rates.
Re: go roller or flat tappet
Posted: Fri Jul 23, 2010 4:16 am
by v8ranger
painterdude923 wrote:bought a 1990 5.0 came out of bronco. would it be worth it to drill and tap holes in the block for the spider to make it a roller cammed motor or just go with a nice flat tappet cam?
Ummmm, isnt it all ready a roller motor??? I took apart a 1990 Crown Vic motor, and it was a roller motor.
Re: go roller or flat tappet
Posted: Fri Jul 23, 2010 5:16 am
by cgrey8
Ford, for whatever reason, made their car engines rollers, but kept the truck engines as flat tappet even though the block is cast as a roller block. They eventually went roller on the trucks, but for some odd reason, they didn't do it at the same time they went roller on the car engines. So what you have are roller block engines with flat tappet cams. And because Ford pinches pennies, they don't bother drilling-n-tapping the valley to accept a spider. But with a drill and tap-n-die set, you can do it yourself.
Again, I highly recommend doing the drill-n-tap to get it to be a roller just because the cam options for HO roller blocks is so much better than it is for non-roller.