Well were about to get the rotating assembly balanced on the 390. While at the machinist yesterday I popped open the pistons box and noticed one of the pistons didn't match the rest. Don't recall this in the past but ? He assures me he hasnt been in the box. so ?? Now I'm hoping Larry of Larry's Performance will make good on these. The box does have the 8 X'd out and a 7 written next to it. The box is a Badger box but in looking over Summit's inventory I have ID'd the pistons as (7) Fed Mogs 381P .030 cast pistons. with one that the only identification is a sun dial inside with 1139 center.

So onto the ? about the pistons. If I have to get new pistons...Summit has the Fed Mogs for 13.99 ship today, all others are around 6/6 or 6/18ish.
In looking through the list there are speed pro Hyps, as well as Keith Black for around 21.00 a piston and then Speed pro has a forged piston for 31.00

Would there be any benefit to getting the cheap speed pro forged for a DD "truck engine". Or even any benefit to getting the Hyp piston for said engine?

TIA...

 

I have always run the speed pro hyps a little extra durability at not much cost a good piston I have run them to 6000rpms in a 289 on a regular basis with no trouble. I wouldnt go forged unless you have too my machinest said they wear more on start up becasue they are more dense and don't expand as fast as cast and hyps so don't use them unless you need them because you are blowing up normal pistons
-Johnboy

 

Larry's agreed to ship out a another 381P .030 no charge. Very cool of them. Since this is just gonna be a truck motor that needs to live a "long life" we'll just proceed as planned. Good to know on the Hyp style, thanks.

 

That's pretty good service from them. Good to hear it worked out for ya. Keep me in the loop on the build. Bet you can't wait to get the 390 in. Should be a nice engine.

 

Well some good news hopefully, we got a call from the Notary with Escrow today and have an appointment to sign the paperwork this evening. Fingers X X'd

Sure will be nice to do one of these in a room big enough to turn around in

 

Well that is good news!!! Wish ya the best!!

 

Glad too hear all the good news Bobby !!! Cant wait to hear the engine fire Vid!!

RJ

 

Hey Russ, where ya been man ? You must be toting the greembacks in a wheel barrel by now LOL

It's a good feeling now man, was just sickening for the last 3 mos Promises up the *** and not a damn bit of follow thru. But we're there and by the end of this month we should be under our "OWN ROOF" ok well the banks roof we get to call our own LOL

But it beats hoping some SSOB is going to pay the mortgage with your rent $ so you have a roof..

 

Good news B!! I know it's been pretty stressful for ya lately. You'll have that HUGE garage to work in now!!! Very cool. Congrats to all!!

 

Just for you Glenn I'm going to roll the FE in on the stand all by itself and get a pict of the space LOL JK


Thanks Bud!!

 

That would be cool!!! Gonna make a nice shop too!!

 

RedBob, IIRC the speedpro 381P and silvolite 1139 are 410 pistons, with a 1.65 pin height. In a 390 with the felpro blue head gaskets, you'll have about 7.8 to 1 compression. Thats not really enough. I wouldn't use them in a 390. Even if they were free. DinosaurFan, on work's old 'puter

 

Well thats Jim dandy Dino, now..... what would you use and why so everybody here can get a lil education instead of a roadblock/.

On a side note I guess that would be a perfect opportunity to switch to the 1UB crank in the shed huh ?

 

Yep it would.

 

Red, if you have already bored and honed the block to the pistons you have, then yes, it is a perfect time to go and grab that 1UB crank and make some use of it. That would be my first choice.

If you are going to keep the truck as a 390, and are going to use gasoline for fuel, you have sevearl choices. Memory gets hazey to all the numbers, but I will do my best. (CRS disease ) You could look at speedpro H395Ps...thats is supposedly a 360 piston, but has a 1.759 height and flattops with 4 valve notches. You could also consider silvolite 1131s, 1116s. If you like Keith Black, they make a KB150 that does well in trucks. There is also an H304P, speed pro, the pin height is correct but it has a rather large dish. If you want to spend lots of bucks, there is the L2291F forging. Very heavy, and tougher than most of us really need. What cylinder heads do you have, what cam, and what are you going to use for fuel ? If you live somewhere that E85 is available, you can use ALOT more compression than most. Is this 390 going to be used like a commuter car, or for truckish things like like pushing snowpiles and pulling trailers ? DinosaurFan, on the log in from his Dad's house