Speed-pro H621p dish volume?

[travis]

I've searched high and low but can't find any solid info. Does anyone know??

[mag2555]

Do you have the Pistons and a CC Burette?

[pdq67]

Or buy a cheap 50 cc plastic syringe from a local Drug Store and have at it.

pdq67

[pamotorman]

I can not find a listing for a H 621p in any listing I found a H 620p with a .185 deep dish with 2 valve reliefs. -21 cc

[Hrdlx62]

Don't forget the clay.

[mag2555]

Holy crap!!!!!!
The only info I can find on that piston after a real long search was on the SP site, and even then all they give is that the dish is .190" deep.
I would inn light of that say that the dish is 4 to 6 CCs no more !

[wyrmrider]

mag
if
.185 deep dish with 2 valve reliefs. -21 cc
then how is
" .190" deep.
I would inn light of that say that the dish is 4 to 6 CCs no more !"
is one a D dish and one circular?

what's this fit anyway

[travis]

These came in a 351w engine that I got for next to nothing. It was a fresh rebuild but he said it smoked like a freight train. I found lots of mistakes...steel roller cam with a cast iron distributor gear, and it looks like it was honed with 40 grit sandpaper. It will need to be bored...at least it was a standard bore. It had TW170 heads but my buddy is getting those to go on his 393w. It was balanced and 0 decked so I was thinking of using the same pistons when I go through it. These have an oblong dish...not circular.

I would cc the pistons but I am 1 handed right now...I broke 2 fingers on my left hand

[wyrmrider]

well bore as little as possible
you should be able to post up the compression height, piston weight rough head cc and pistons can be matched up
what compression are you shooting for and which heads are you going to use
I did a search on the SP site and found nothing so you did better than I did
If it's an older piston I could check my paper catalogues

[superpursuit]

The last time I checked the dish on a 351W oblong dish piston [these pistons suit efi 351W engines] it was 14.5 cc. This was a different brand of piston to yours but this should give you an idea. I would think the different brands are very similar in dish size as they are an OEM replacement piston. I hope this helps.

[ProPower engines]

Why not just call FM direct and ask for their tech guy to get the info.
Since it's a cast piston any details are approximate anyway.

Their number is 1-800-560 1400 follow the prompts

[wyrmrider]

you got a 0 deck with a replacement piston?
do post up the CH and if you do call ask if the piston is "compensated"
compensated means they took .015 or so off the compression height to "compensate" for the compression the increased bore would give-and in the process kill your quench
looking at the KB line I see 1.774 Comp ht for 5.956 rod
0 cc flat top
2cc flat top
6.5cc flat top
11 cc Icon forged
15cc step dish for N head
19.5 cc d cup
22 cc d cup
if you click on the picture on the left column you get all the details like which deck height rings etc compression ratio with head cc and weight

the 1144HC cast piston comes with a 1.719 ch 5.5 cc
1158>looks like12 cc a d dish but succeeds to 3330 which has .240 deep rectangular 1.720 ch
1171HC 1.752 CH 12.5cc looks like rectangular recess .105 deep
3154h ch 1.770 17.5 cc rectangular 180 deep replacement hyper piston not a KB not compensated (.004)

so you might be able to match yours up
bvvc with the 351W as you have two different deck heights
let us know what you come up with cus I have to build one for my bronco

[mag2555]

Your right on my CC math as I forgot to convert CI to CCs!
With assuimg that from what I have seen from a shot / photo of that 621 piston that the dish area covers 75 percent of the top of that piston I am getting like a 29 CC dish!

I still can not belive it's not possible to find out this info out of the company catalog that this piston comes from, it's sad and madding at the same time!!!

[travis]

The cast 463P pistons measured 17cc last time I did a set. They are very similar in shape to the 621's. One big plus that I see for the 621's is they have a 1.784" CH...much less decking required to get a 0 deck. However if they are 17+ cc's they won't get me where I want to be.

This info really shouldn't be this hard to find!

[wyrmrider]

.010 more than the KB good to know
travis
won't get me where I want to be.

WHERE DO YOU WANT TO BE and what's your head cc, gasket etc
early short deck or late block + .020 taller

super- you have to keep in mind the compression height distances make a big difference as well as the cc's any idea what the ch was on your pistons?

anyway I like to build with a tight quench- three variables (unless I offset grind the crank or offset bush the rods)
gasket thickness, deck clearance (compression height) and dish volume