Inliners International Forums General Discussion Hi Performance 307 piston pin height

YES and as to the 1 or 2b I don't think it mattered once they got done with it. Mind you most of these were used mostly for Racing.

I'm saving my integrated head now!

My understanding is that the integrated head with the intake portion cut off becomes a 12 port head, as the intakes ports aren't siamesed inside. The monojet head is restricted by the single barrel mounting point, but it does have a 2.25" exhaust manifold. So with a 2bbl with adapter, good valve job, increase in compression, basic street cam/springs, and 2.25" single exhaust it would still be a pretty good street engine. I think the 205 truck integrated head would be better yet with it's two barrel carb mount and the duel 2" exhaust outlet manifold. Nothing wrong with an integrated head for a daily driver street application.

OK. I stuck this on the other 307 piston thread. I get confused easily. I was doing this in response to Intergrated j 78's request.

OK, Here's what I got. My measurements are somewhat crude but should give you an idea. I used a caliper as well as I can. The 307 pistons are .040 over as marked on top. There is a dish and two valve cuts. The dish is 2.995-2.93 wide and .050 -.058 deep. Without the valve cuts that about 5.8cc to 6.4cc. That is probably a little bigger than the 250 dish but it does not have the hugh chamfer that the 250 and some other 307s have. The rim on top is about .045" wide and would give a nice quench area. To get the pin height I measured from the top of the pin hole to the top of the piston and added 1/2 of the pin diameter. The 307 measured 1.64856" -1.65365" and the 250 was 1.63875". It could be closer to the 1.655" advertised. So the 307 is roughly .010" taller with a more efficient design. I think it would help some but not a lot. The box they came in may not be the original box. It may be worth more a sports memorabilia than the pistons are worth. It says Zollnor and Fred Zollner was the founder of the team that became the Detroit Pistons. There is a hand written part number on the box. It is a Sealed Power number. 295 AP 40 is the one with 4 valve cuts. The rings are Sealed Power KromX. I mounted one to check it in the 153. The rest haven't been messed with. The pins are stuck from dried lube but will come right out with some degreaser.

I'm not in the piston business so if you want them I'll make you a good deal and there is no hurry they are not going anywhere till you know if you can use them.

Thank you for taking the time to measure those pistons for me. Everything that I have read about new 250 pistons either say that the dish is either .085 or .115 deep depending on brand of replacement pistons. The pin measurements match the published specs for both pistons. If I need to overbore I would be interested for sure. Maybe str8shooter will need them sooner. While the tools are out can you please tell me how deep the dish is on the 250 pistons that you have. Jay 6155

I'll do that tomorrow. I don't think the dish on the Silvolite 250 is that deep but we'll see. We'll see what you and Dan want to do.

Found this data in a Sealed Power catalog that can be helpful. It lists(2) pistons as replacements for the 250.

L2314F- C/H is 1.672,Flattop w/4 reliefs and a volume of -2.5cc and also a -.025" deck height.

L2396F- C/H is 1.655, .073" dish and chamfer with a volume of -11cc

The first one sounds interesting. In my 4 cylinder build that would be really close to zero deck and less expensive than the Ross pistons I got but also not forged if I go to the next step. Crap it's taking years to get to the first step.

CNC-Dude there are 2 of theL2314F pistons (std) on ebay for 39.99 each. They are forged. Napa,Autozone does not list them. I called my friend at Advanced auto parts It's a good number but they can't get them. Haven't checked anywhere else. I will let everyone know if I do find them at a different parts store. I looked on the sealed power web site and they don't show them either. (Maybe I am just not using the sealed power website the right way). Beater thanks in advance for checking the 250 piston for me. Jay 6155

Sorry, Long day and I didn't get out there. Get it as soon as I can.

No problem. I don't mind waiting at all. Jay 6155

Jay, What is going on with your build. Are you still waiting on me to measure something? I got lost. I made a test pin so I could check the height of my Ross pistons and they are perfect. In the pictures the Ross 250 is shown with the 307.

Beater, I waited until today because my Grandson was coming over and we could work on the engine together. Sometimes time with him is limited as I work and he is very busy. Today we tried to get the head off so I could check for bore wear and measure the stock pistons. We got as far as just the headbolts and dist left to go when we ran out of time. I could do this myself very quickly but that is not the point. He gets out of school soon and we may be able to go faster. I did find out that the exhaust manifold is cracked. Will take it to work and see if we can weld it as it has dual exhaust outlets. Those Ross pistons are purrrdy. Jay 6511

Damn the 2bbl integrated exhaust was cracked. That was one of the focal points of the project. Hope it welds up easy.

I probably have a extra. They usually go into the iron pile.