Has anyone every heard of using hydraulic lifters with a flat tappet cam? The guy that is doing my head work said that this would be a good way to not have to adjust valve lash and would have some performance improvement over solid lifters.

I think you need to find another engine man. This one doesn't know slants.

_________________
Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 170 nitrous
64 Valiant Signet
64 Valiant 4dr 170
64 Valiant 4dr 225

Going to hydraulics does get rid of lash adjustment but putting hydraulic lifters an a mechanical cam profile will not increase performance.

The ramp design for a mechanical cam has a real slow and easy lead-in to softly take-up the lash before going into the lobe "flank".
A hydraulic profile is just the opposite, the lead-in is aggressive to quickly compress the oil in the lifter's chamber so it acts solid as it goes into the lobe flank.

To put hyd. lifters on a mech. cam would make the engine run as though it had a smaller profile cam because the hyd. lifter on the 'slower' mech. cam's ramp would allow the hyd. lifter to "bleed-off" some of the cam profile.
DD

My Engine man recommended the guy to port and polish the head which he told me he is pretty good. He has a flowbench and he did base line flow and he flowed it after the port and polish and he got a 29 percent increase over stock. I guess that is pretty good i'm not sure. I was talking to him about maybe finishing the head lowering the valve guides and installing the valves and lifters and doing a 4 angle valve job and thats when he said I could use hydraulic lifters. I talked to my engine man about the hydraulic lifter and he told me that he was going to finish the head because the guy doesn't know what he is doing in that part of the job.

pvaliant......You say that the head re-work guy did a baseline flow bench test on your head. Did he give you a piece of paper with the numbers on it, or a graph?

If I recall correctly, wasn't someone here looking for just such info?

Roger

He did put the baseline flow and the flow after he ported and polished it on a graph. I haven't got it from him yet because when my engine man finished the valve job and all the other stuff. The heads going back to him and he's going to unshroud the intake side of chamber and reflow it. I don't completely understand everthing but he said that he's trying to get the ratio between the exhaust and intake closer to 75% right now he said it is between 80% to 85% which he said isn't where it would be the best.

sorry didn't login

Well, if you get those numbers, would you be so kind as to share them with this board. There's a bunch of guys here that would probably like to keep them on file for future referance. Performance info, especially more technical, is a bit hard to come by, as the bigger shops don't really play with inline engines.........everybody's gotta have a V-8.

Roger

i'll second that...i'd love to see some flow numbers for a slant head. i haven't been able to find any on the net.