The Stovebolt Site Forums The Shop Area General Truck Talk Finally,pistons

Trying to get Ross Piston to make a set for my 302 GMC project is a study in fustration.
A call to Venolia got results, they actually sounded happy to make them for 100 bucks less than Ross, takes about 4 weeks.
I made a Plaster of Paris mold of the head combustion chamber with the headgasket in place to show the cylinder circumference in relation to the chamber.Send that mold and an old stock piston so they can engineer the compression ratio I want.
I'm bushing down the rod small end to use .990 lightweight Chevy big block wrist pins instead of the giant 1.15 pins used on rods I got.

Been quite a while since I had to get pistons and then the machine shop got em for me. I saw that Sixpac used venolia for his 302 but this plaster of paris game is new to me--what are you makin some super race engine out of this lump? Custom domed pistons huh--have you figured out a way to turn that 302 into a hemi?

Joy was complaining about having to keep track of all the different fuels to fill up your hi compression engines. Prolly have to send her out to the airport for jet fuel on this un.

It's only 9-1 compression, but with the large 120 cc chambers, gotta have a small piston dome, 25 cc's. The dome has to be made properly to keep a good quench band and a quick mixture burn.That's why they need a mold.Plus the 302 has a somewhat short con rod, the piston pin is kinda low on the piston.So the piston needs a fairly long skirt to keep it from rocking around.Venolia had solutions where Ross only had uncertainty
I'm doing the leg work to save cash.

That sounds like an experimental short-stroke smallblock V-8 I'm building! I'm using a crankshaft for a 262 V-8 in a 305, with 6-inch rods. The pistons come .085" out of the top of the block, so I machined the protrusion into a dome to help the compression out a little. With a set of 58CC 305 heads with big valves, I should be able to run mid-grade gas without detonation problems. With the 3.1" stroke and a roller cam with a rev kit, I'm expecting to be able to turn 7,500 RPM or more. Look out, track record!
Jerry

I have a set of Ross pistons for a 302 It was no problem at all to get them.....but then they don't have a 'T-dome'
The head has a flat combustion chamber I guess they make a lot more of those and understood.

I have and still use Venollia There in LB and I've been buyin pistons since I was 14 there. Be sure you follow Tom's bore clearance spec. I don't think they have a hi-sy forging for that size and you'll need to make the hole really big!

See if he can get you Deves Rings for that bore.....they may seem low tech to you but work much better than Total Seal

Say hi for me tell em I be over after I return...Both Ross and Venolia have really nice people working there Sound like you just got the wrong guy.

Which Three pot manifold are you using?

Jim, I'm going to fabricate the intake from sheetmetal.Wayne Mfg wants 450 bucks for 3x1 intake, and I haven't found any used ones.And a few well know Inliners told me I can't make one, good enough reason to make one. I may change my mind though
And I will try the Deves rings

I cast a mold of the cumbustion chamber using Plaster of Paris,lot's a fun actually.
This photo shows the finished mold ,painted and ready to sent to Venolia Piston.
Castings R us
These other shots show the head gasket clamped to the head to show the cylinder outline,chamber greased with Vasoline as a mold release and a shot showing the plaster poured into place.
Head
Plaster curing
The valve seats are done,Chevy V-8 valves, 1.94 intakes,1.60 exhaust.The head will be milled a little once the engine mocked up to check clearances.
The Vasoline is also useful to lubricate by butt when I get the bill from Venolia