8 TRW FPP 2971 New In Box

[chris401]

I found std bore 410 pistons w/pins. $400 a fair price to pay?

[ScotiaFE]

2971's may be +.030's
Best to measure them.

[chris401]

I saw that same thread on fordfe. 4 1/32+ is satandard for a 4.05 bore. Unlike my digital Snap On the old fractional mic does not die laying in the tool box.

[ScotiaFE]

4 1/32 = 4.0313" or there abouts.
My old data shows it as a 30 over.
Still best to measure the skirt with a micrometer.

[chris401]

4 1/16 at skirt. The machinist that had them said they were .020 over. He had so much of the Big 3 I didn't think he remembered. Looks I was wrong again. Does your info give any price or durability info.
Thanks

[chris401]

Quality? Don't want to mislead buyer if they are poor quality.

[ScotiaFE]

Old TRW's are as tough as an old anvil.
Almost as heavy too. lol

[chris401]

Good to hear. These were the first forged I have dealt with, didn't know they were that small up top. Makes sense if your getting the chamber hotter. Every engine I have done I would have to hone to fit with .002 to .003 clearance. Would this be acceptable with forged if it were sprayed?

[My427stang]

Man I think those old TRWs grew a lot.  I think they have to be pretty loose, I don't have a book near me, but I seem to remember .006-.008 for a 427, smaller bore might take less, but I wouldn't go tight

Matter of fact, for 400 bones I'd probably be ordering a modern set of pistons which weigh less and you can get exactly what you want

[fekbmax]

I have ran several sets of TRW 12-1 pistons in .030 over 390's back in the 80's and 90's and always went .005 on the clearance. .002 or .003 more on engine's using a decent shot of NOS. I agree with my427stang and think that $400 - $600 would get you a nice set of modern pistons that fits your needs. $400 seems a bit pricey for the old school TRW's to me. If you could score them for a couple hundred bucks then id call that a decent deal.
Im sure alot of you guys remember knurling pistons back in the day to tighten up on the clearance. 

[My427stang]

Im sure alot of you guys remember knurling pistons back in the day to tighten up on the clearance. 

Yes indeed, mention it today and people think it'll explode when you turn the key!  Used to be very effective with a loose one

[Nightmist66]

Im sure alot of you guys remember knurling pistons back in the day to tighten up on the clearance. 

How about knurling valve guides? Also, it is a no-brainer to go with metric rings on any new piston imo.

[My427stang]

We knurled valve guides, too, matter of fact I only sold all my guide knurling tools a couple years ago.   Had some neat Snap-on kits.

I didn't like to do that as much, especially since the liners are so cheap and easy, but if it was a budget ride back then, had to help the customer

[fekbmax]

Old school days indeed.  We are so lucky now to have all the aftermarket stuff available,  especially for the FE. Of course the science of pride and accomplishment of working with old factory stuff and the limited aftermarket parts was always rewarding.  I know some of you guys remember pining the old press in studs on the small block ford heads..