Curious if anyone knows if hypothetically two engines where build to achieve the same HP on a street driven car if there would be any noticeable drivability differences between one with a flat tappet solid lifter cam and a hydraulic cam? I think there was an Engine Masters episode where the HP differences between solids and hydraulics was very minimal on the dyno, and the real advantage of the solid is higher rpm use to avoid valve float - aka high shift point race car type stuff?

From what I understand hydraulic lifters don't operate with the full effect of the cam profile at low to moderate rpms due to less oil pressure that creates some slack in the system? If this true would a solid cam setup making the same HP have any advantage as far as faster response on acceleration when just driving around? Say accelerating from a roll like passing someone on the highway, etc. Does the oil pressure in hydraulic lifters go up so fast you can't tell one from the other? Majority of people build hydraulic setups for street type engines for no maintenance use, but are they really getting the most responsive setup for driving around with?

I looked around on the internet and can't really find anyone talking about solid cams as far as if they provide a different driving experience at all.


EDIT: Read the 2nd comment down from the top in the video that kinda covers it maybe. He is talking about roller cams, but wonder if this would also apply to flat tappets? https://youtu.be/GZTdo2-cGCM?si=xiXzrgD5dXZ_u7LU

i've run two similar combos, not identical by any means, but from the switch from hydraulic to solid, there was a noticeable difference in driveability going to the solid cam. the idle was better, the off idle response seemed better, the hydraulic while it would pull just fine. things with the solid seem to happen just a tad quicker. both were comparable, and other than that i have no dyno numbers or timeslips to back up the feelings, just what i observed. i was happy with the hydraulic, but wanted to try the solid. i think the ramp profiles were a little steeper on the solid. again anecdotal at best and it was a bunch of years ago. today if budget would allow i'd go roller cam and be done with it. solid did add some maintenance with lashing vales about 4 times per year and mostly that was just checking but did take about a hour or two depending on how many interuptions i had.

From my experience running "similar" (not identical) cams of both hydraulic and solid flat-tappet, that's it.

If there is any drivability difference, I've been too numb to notice it.

This article is about 20 years old but the data is still good. I tested mostly solid flat tappet cams in my Coronet but then tried a hyd flat tappet as the last test and it was my favorite. It revved just as well as the solid flat tappet cams and was much quieter. The numbers were all close to the same but for some reason this cam just "hit the spot".

http://www.moparts.org/Tech/Archive/bb/Lobe.html

The benefits of a solid regardless of performed gains is worth going solid. You never have to worry about collapsing or pumping up a lifter. The maintenance of a solid is way over stated. I check once a year. Which is like a physical for your engine. Lash opening up? Early warning sign.

You look at guys who run small block Chevy engines way back when with the stock press in rocker arm studs, and think about where this need to constantly reset the lash stories came from. Stiff valve springs and high rpm have been known to pull those press in studs up out of the heads a little bit at a time likely creating a need to set the lash more often. A Chrysler engine with the rocker shaft setup is likely going to be more stable compared to other engines.

There is a good thread about solid flat tappet cams on the street on the H.A.M.B. website where guys are logging some decent street miles with few if any adjustments being required. Not race spec cams, but street type configurations.

This is more in line with what I find is typical in high performance BB applications running HFT cams.

https://www.motortrend.com/how-to/mopp-0510-440-engine-dyno-test/

Wow I never saw that article, a 275HFT is what like 230/236 @.050? Hardly Near Stock @ 050.

What was the 440 Mag cam ? 268/284 Advertised and .450/.458 lift? (so maybe 210/216 @.050? Anybody know for sure? I always wanted to know. I know it's not the .85 of Advertised they claim for Purple shafts)

That really pretty great torque for that small a cam with a nice head and intake. Still I think 370# over the nose is a lot to ask for about any Hydraulic Flat Tappet, I'll bet it was already in partial collapse at anything over about 5200, but that was perfect for the Solid. With a more modest 320-ish Spring I blet the difference wouldn't be all that much.

Unusual to see super high CR with that short of valve timing. But still it shows a big port / small cam gives you a way better torque curve/Average VE and hight HP potential than a lot of people realize

Having solids in a street driven gen 2 makes me numb to internal engine noises because it always sounds like it's coming apart. I'll never go back to HFT though.