JRP's Unofficially, Official Regal Thread

joesregalproject

joesregalproject

Comic Book Super Hero
Nov 4, 2012
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Pittsburgh, PA
Stopped at the machine shop this morning and got an update on the engine. The crank is all measured up and will be sent out today or tomorrow. It'll probably be a month to get it back. In the meantime, the block will get decked just enough to true the block, probably .005" or so. The rods will get reconditioned, cylinders will get bored and honed, the cam bearings will get pressed in. I sent my balancer out to Dale Manufacturing in Oregon so they can rebuild it. They are off in December so I should get it back early January.

Also we looked at the pistons a little more and it looks like I'm gonna end up with the forged autotecs, which are advertised at 9.75:1, though once I true up the block and heads, will probably be around 10:1. I don't want to go too much higher than that, but if need be I can use a thicker head gasket. Main reason I'm not going with the 340P is because the 340P is heavier than the stock piston, so I'd have to have tungsten slugs put on the crank to get it balanced correctly which would make the price of the balance job go up and offset any savings. Plus the Autotecs include rings which is another $100 or so I would have to spend if I went with the Sealed Powers.

29734at350buick-jpg.100835
 
MrSony

MrSony

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Nov 15, 2014
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Des Moines, Iowa
.005 isnt gonna do much. When I get home in 8 hours ill mess around with my compression calculator and see what it takes to get to 10:1. Tbh with the open chamber iron heads Id stay at 9.5 or 9.75:1. Crower level 3 cam for a dynamic comp. ratio under 8:1 for pump gas.
 
MrSony

MrSony

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Nov 15, 2014
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Doing some maths, most smog buick 350s have the pistons about .060 in the hole. TA lists the factory piston compression height of the pistons as 1.875, .025 more than the pistons you are going to go with. The "9.75:1" pistons have a 13.5cc dish, the "flat top" pistons, also from autotec here, have a 4 cc dish with valve reliefs, like a standard SBC piston. The "9.75:1" pistons with the shorter compression height than stock will be at 9:1 or below. The "flat top" pistons with the 4cc dish will be at 9.9:1, with the same 1.850 compression height. Keep in mind, you can order them to whatever specs you want for either type of piston. Just be sure to get them with the .940 pin, that's the stock pin size for the buick rods. Order the pistons near the end of the build. You need to see what stock is for a reference point. When the crank comes back (or if he still has it), tell him to measure how far down the pistons are in the hole and the compression height of your stock pistons, and go from there. Also, there are only 2 headgaskets available really for SBBs: the standard .042 (thickest) felpro deals, and the .020 (thinnest) TA gaskets. And make sure he gets the damn flashing from the lifter valley, if that's not already done. besides the "oil issues", that is one of a Buick's biggest downfalls. It doesn't happen often, but when a pea sized flake of cast iron falls onto a cam lobe, sh*t hits the fan very quickly. TA also sells stock replacement flexplates, if you were wondering. I don't think they make them, I think they just sell them. Mine came in a Pioneer box.
 
joesregalproject

joesregalproject

Comic Book Super Hero
Nov 4, 2012
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TA lists the factory piston compression height of the pistons as 1.875
That number doesn't sound right. My pistons only measured 1.810, and they are the original GM pistons. I'm gonna call T/A and see where they got that number.
 
joesregalproject

joesregalproject

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Nov 4, 2012
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So I called T/A and they confirmed my suspicion. The stock pistons are nowhere near 1.875 comp height. Guy at T/A said he had no idea why they wrote 1.875 in the catalog, but it definitely isn't correct. I told him mine measured 1.810 and he said that sounds about right.
 
MrSony

MrSony

Comic Book Super Hero
Nov 15, 2014
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Des Moines, Iowa
So I called T/A and they confirmed my suspicion. The stock pistons are nowhere near 1.875 comp height. Guy at T/A said he had no idea why they wrote 1.875 in the catalog, but it definitely isn't correct. I told him mine measured 1.810 and he said that sounds about right.
I always thought that number seemed a bit high... maybe it was for the '70SP pistons...? idk. If that's the case then, the autotec pistons will be a great fit then. I really wish I would've measured mine.
 
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joesregalproject

joesregalproject

Comic Book Super Hero
Nov 4, 2012
2,536
1,831
113
Pittsburgh, PA
I always thought that number seemed a bit high... maybe it was for the '70SP pistons...? idk. If that's the case then, the autotec pistons will be a great fit then. I really wish I would've measured mine.
That's what I'm guessing. The 340p pistons are 1.835". Federal Mogul makes one that is 1.800". The crankshaft is sent out already but Bob the machinist got all the measurements before sending it out. I'm trying to remember but I think he said the pistons sat around .065" in the hole. Like you said, I don't have to buy pistons until toward the end of the build, so there isn't much rush.

I do have to start looking for a cam. How do you like your Crower 3? I'm sort of between the Crower 3 and the T/A 290. I'm not set on anything yet but I'm gonna go with a small stall converter and heavier springs either way.
 
85442/86buick

85442/86buick

Master Mechanic
Feb 12, 2013
390
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Toronto
have you looked at the Comp Cam 268H ?
Mr Sony had one in his first built
 
MrSony

MrSony

Comic Book Super Hero
Nov 15, 2014
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The 268H would be a good cam if it wasn't a symmetric grind. SBB with their admittedly very poor (compared to other small block 350s of the era, even in the pre smog engines) exhaust ports need a cam with more emphasis on the exhaust side. The crower and I think ALL of TA's cams do that. I bought the crower off of summit, it was cheaper. It put my DCR with my "10.25:1" SP pistons (not the 340p, the actual factory 10.25:1 code SP engine pistons. they had a slightly higher compression height and a shallower dish, a few cc shallower than the 340p), at about 7.8:1. I'm also using .042 gaskets so I'm no longer at 10.25:1, more like 9.5-9.7:1.
The crower has less lift on the intake than the comp, but more duration on both I and E at 276/281 respecively. The crower is also on a 112lsa compared to the comps 110, so it does a little better in producing vacuum. I've got 17" right now. I've had it as high as 19 but I had to back the timing off and that lost a little. my vote is crower. retard it to 4* retarded and it's worth 30hp. Need the TA 9 way keyset to do so though. Unless you have your engine guy degree it.
edit: and the backing the timing thing off, I had it at 12* with the 19", but it didn't like it. I've messed with the weights and springs since then to change the curve, so I might be able to bump it back up, it's at 10* now. For my future comment, it was at 8* on my dyno run.
 
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