Chitown racer

uuuuuuuuuuuh ok, if you say so. Although, Ive been building motors and working around High performance cars for 20+ years now and as far as I know anyone who knows anything about cars refers toany piston without a dome and with or without valve reliefs as a flat top. Unless of course it has a dish or other type of distinct recess in the top then we call it a dished piston. While technically I suppose you might consider that slight recess in the top of the 5.0 piston a dish most people refer to all the 5.0 H.O. pistons regardless of the year as a flat top.

86 5.0L

ok but...

have you looked inside an 86 5.0? those pistons are COMPLETELY flat, no notches, reliefs, cuts, domes, dishs, nothing....

just flat

heres a bad picture of some 86 pistons, kinda hard to tell though...

Chitown racer

Yes I have and thats exactly my point. He called trick flows tech line and as I'm sure the guy that answered was knowledgable about cars he would have referred to any stock 5.0 H.O. piston as a flat top. What he needs to do is call them back and explain that he has an 1986 5.0 engine andthat it has no valve reliefs at all and see what they say.

86 5.0L

I see we're arguing the same point[8D]

Chitown racer

So we are....lol

capri debris

I told them at T/F that I have an '86 Capri 302 with flat top pistons, he said that's the year they didn't have any reliefs cut into them right? I said you're exactly right, so what about valve clearance? He said no problem, but still check by claying it up. I waited a few days then called back and talked to another tech guy and he told me he was pretty sure it wouldn't be a problem but put me on hold to check his info... then he came back on and said yep, you'll be fine.

my77stang

but if you are tearing everything apart why are you sticking with a standard bore anyways? there HAS to be a ridge at the top of the cylinder which means your already loose in the hole. then your going to hone it and take probably another .0005 (half a thou) not to mention if your not REALLY carefull a ridge reamer can do more harm that good, and without getting the ridge outta there you will destroy your rings and they will never seat properly. if you have a larger budget than the other guy who said his was over 4k, some of the best money spent will be boring and getting new quality pistons. get your crank reground too, have them deck your block, and recondition your rods WITH ARP 5/16 BOLTS!!!!!! then you can have them balance your bottom end so you can rev the damn thing without blowing it up and it will last you alot longer.

do it right, or do it twice - trust that shiat

capri debris

You're absolutely right with that advice... however. I restored my other '86 Capri about 7 years ago and when I tore the motor down at 148,000 miles, there was almost no ridge present in any of the bores and the crank looked brand new. So I mic'ed all the bores to check for out of round and all were within acceptable limits, so I just honed them. I held the tool at the top of each bore a little longer to smooth out the very small ridge that was there, then mic'ed it all again. When I test fitted the rings, there was enough springin them to seal against the cylinder walls and I still had to file off some material to get the end gaps correct. I've put about 30,000 miles and alot of track time on that motor with no issues. I thought I just got lucky with that motor, but when I tore down the motor I'm building now at 152,000 miles, it was in the same condition as the first one. So I'm going to do the same thing for this build... my motto is, "If it aint broke don't fix it". This way, I can keep from spending all the extra money for boring, new pistons and a balance job. Besides, I don't think I'll ever miss the few extra cubic inches I'd have if I had it bored out.

my77stang

i wasnt saying it because of the extra cubes i was saying it because of reliability and the generalization of doing it the *right* way.

sure you can do it cheap, and it may work just fine - but coming from a machine shop its hard for me to accept a performance build with a skimped out bottom end.

just my .03 [8D]

Chitown racer

Well I guess if the experts at trickflow say its gonna work it must be true. I'm still skeptical myself, but be sure and let us know if it works out. Remember though, you need a minimum PTV clearance of .100" on the intake and .080" on the exhaust valves.