what is the maximum lift that can be applied to stock pistons in an 89

trickflow5 · 02-08-2007, 07:32 AM

I have a few questions. I was wondering if anyone would know the max. lift
that can be applied to stock pistons to ensure the valve would not hit it. I have heard not to go higher than .520. I am thinking of building a 331, 347, or stroking a 351. If i purchased the pistons cut what kind of lift could I use? I wanted a monster NA engine with close to .600 lift is it gonna be possible? I am going to be using 2.02/1.60 valves. I don't think that will factor in any though.

**MonteCitan** · 02-08-2007, 07:50 AM

its not just lift you have to worry about its duration, when the valves are still open (overlap) with the piston coming close...

bbunt302 · 02-08-2007, 10:38 PM

Monte's right. And regardless of whether or not you "hear" a cam is safe, you should always measure piston to valve clearance before you fire it up.

trickflow5 · 02-09-2007, 09:50 AM

I will be going with the trickflow stage 3 camshaft which is 574/595 lift and 298/310 duration. I was thinking 6.25 inch pushrods would do the trick. Does anyone have anything similar to this setup?

bbunt302 · 02-09-2007, 09:53 AM

That's never going to work with the stock pistons.

trickflow5 · 02-09-2007, 10:46 AM

I'm going to have the pistons cut. The bottom end won't be stock. I was just being curious as to how high anyone went with the stock pistons. the cam I have now is a .499/.510

bbunt302 · 02-09-2007, 10:51 AM

I've got a .512/.512 right now with stock pistons. 270/276 @ .006", 218/224 @ .05". It has done absolutely fine.

I was considering putting 1.7s on it for a long time, which would have brought the lift to .544"/.544". I was afraid I might run into issues though, so I never did.

bullitt482 · 02-09-2007, 04:24 PM


Quote: Originally Posted by trickflow5 I'm going to have the pistons cut. The bottom end won't be stock. I was just being curious as to how high anyone went with the stock pistons. the cam I have now is a .499/.510

Let me know how it goes, I've got the same cam. I'm thinking about finding another 302 and making a 347 using the Track heat kit that I already have with it. It would definately need a bigger cam.

silverstangboy · 02-09-2007, 05:35 PM

ok, the biggest problem I see here is the usage of 347/331 and stock piston...

not gonna happen.

trickflow5 · 02-10-2007, 07:17 AM

i was just being curious about the highest lift with stock pistons. so far it is 512/512. my pistons wont be stock.

silverstangboy · 02-10-2007, 10:53 AM

like others here have said, it has nothing to do with maximum gross lift numbers, and more to do with actual duration and ramp rate design! as the piston is nowhere near the valve at maximum lift!

svtlx · 03-17-2007, 07:30 AM

i am run'n .529 lift with true flat tops (no valve reliefs)...e cam .498 lift with 1.7 rollers....it was damn close....i am probably wrong, but i think .544 is as high as u can wit stock heads and pistons..any more than that and u will have to make sum deeper cuts in your valve reliefs. but like silverstangboy said, u have to take into account the duration...i would leave a small margin for error by taking into account heat expansion and max rpm. ford racing said my set-up wouldnt work...it did until that bitch got hot! i had flat top pistons w/o valve reliefs...needless to say, after it got hot the motor made its' own valve reliefs...didnt bend the valves, but 3 outa eight pistons have homemade valve reliefs now.

Matthew · 08:12 PM

I ran a stock 90 short block with TFS track heat heads, Fel Pro 1011-2 gaskets, and a trick flow stage 2 cam installed straight up and it was fine. If I recall, there was about .120" intake clearance and about .240" exhaust clearance.

As others have said, it's really the duration and ramp rate that matters. If I recall, exhaust lift on that cam was .569. You should check every time you install a big cam, and it's really a good idea to check at least one cylinder on each side. If it is really close check front and back on each side because your deck may not be perfectly square.

I think you will find that most guys suggest absolute minimum cold clearances for a hydraulic roller setup to be .080" intake and .100" exhaust.

-Matthew

svtlx · 03-19-2007, 11:37 AM

yea, wut matt said...now pay the man!!!!!

silverstangboy · 03-19-2007, 04:48 PM

Welcome aboard Matthew, I love to see people here with more experience than me.

hang around for a bit.

Matthew · 03-19-2007, 08:11 PM

Thanks for the welcome. Silentnoise, who is a member of the same car club as me and apparantly a moderator on this forum invited me to come over, so I thought I would give it a shot. Seems like a good board. I'll try to help out when I can.

-Matthew

SilentNoise · 11:36 PM

Hey man, welcome aboard. Good to see that someone took my invitation finally.

Ya, Matthew knows his shit. He's an encyclopedia of knowledge when it comes to Mustangs. I suppose it shows since he runs his own dyno shop and has built his own 10-second, naturally-aspirated Stang