my friend has a 56 chevy and wants to build up a 350 engine for it hes got a 71' 4bolt block bored 30 over, not decked,and with forged gm crank also has a pair of GM Performance 25534421 Small Port Vortec Bowtie Heads, 373 gears and 350 turbo, my question is what pistons are good for a beating he wants to drive this at the track and to the store. so he needs somthing that will last he was looking at the SPEED PRO Chevy 350 Forged Flat Top Pistons with Floating pins seem to be a good price ? give me some input as to quality,experiences ect ect thanks
SRP/je , MAHLE , ROSS , to name just a few.... he might look into a piston kit with the rings that match...seems like a lot of piston companies are offering that type of deal....
SRP (JE's "budget" brand) would be a good choice; also Diamond or Ross. Probe would be another to look at. Actually, being a straightforward 355, there are a LOT of good pistons that fall into that price range. The Speed-Pro pistons are not as good as they used to be; they are also extremely heavy by modern standards.
I would cc the heads just to know what compression I had as some of the vor-tech heads are rather tight chambered >>>>.
this is what the numbers are on them 2.00 in. intake valves and 1.55 in. exhaust valves. The deck surfaces are .450 in. with 66cc combustion chambers, 185cc intake ports, and 65cc exhaust ports
Not for nothing, why did he have a bore job done without having pistons on hand? I've always taken the actual piston size into consideration before doing the boring and finish honing. Bob
Depends on what your doing with the motor....race, street, strip/street, blower, etc. Forged aluminum will always serve you well. Mahle, Diamond, Ross all make a "kit" which includes W-pins and rings already sized to your bore. Can't hardly go wrong with any of em listed.
Mahle is definitely the way to go. My latest set is for a 427 LS motor I'm building. They're so pretty I didn't want to put them in the block.
Hes not going to use NoS or supercharger, but does want to run it hard on the track and drive it store type a deal
no matter what he gets he needs to take the whole gettup to a machine shop, the right way to do it is to have the cylinders bored to what the piston manufacture specs are if you put a forged piston into a block thats bored to a cast piston it will be to tight and you will eat up a set of pistons faster than you want to
303, does he plan to use this with pump gas, & if so, what octane? What rods does he have (or plan to get)? What budget does he have for the engine? Has he chosen a cam yet, and if so, what is it? What does he expect this engine to do? You've said that it needs to be able to go to the store and to the track, and isn't going to use power adders. Does he want reliability over power? It sounds like it (which is fine). This will determine what he needs to buy. This will all help to narrow things down.
Yeah, what he said. I'll be the first to admit that most of my engine building experience has been with motorcycles, and your basic American auto engine probably has much more room for error .... Still, no way would I consider boring any engine to some arbitrary oversize, then toss in a set of pistons that are supposed to fit.
He will be running pump 91 octane fuel, these are the parts he has got with the deal so trying to use every thing here block-3970010 4bolt main not decked and bored 30 over crank-39411182 forged rods- Eagle CRS5700B3D 5.7 H Beam heads 25534421 GM Performance Vortec small port Bowtie cast iron cylinder heads 2.00 in. intake valves and 1.55 in. exhaust valves. The deck surfaces are .450 in. with 66cc combustion chambers, 185cc intake ports, and 65cc exhaust ports.machined for 3/8 in. screw-in rocker studs, large valve spring pocket machining, and will accept up to .530 in. lift camshafts ? carb holley 650 dp intake TM-1 Trantula It had no pistons,cam ,or oil pump when picked up Im just trying to help a buddie, get his stuff to all work together his budget is not large he just traded things to end up were he is now with the help of you guys here on the h*a*m*b maybe he can get it up and going
I no what your saying. But the block was already bored when he got it, So he more/less has to work with what hes got
Take the block to a good machine shop,buy the pistons from the shop even if you do the assembly.Been my experience many shops will get what you want at a good price.
That intake isn't going to work with those heads. Not up to the full performance potential of the Vortechs.
Buying parts from a machine shop is a good idea. It builds good will with them and they have more incentive to stand by their work. My earlier post was about having everything on hand to get the best possible results. I'd be skeptical about a shop that would bore an engine .030 without having the mating parts. Was the finish honing done? This is usually how I like to bring bores to their final size, so there may be a few thousandths to play with yet. Bob
It sounds like he bought a pig in a poke minus the pistons. I would for sure take the block to a competent machine shop and have it checked out to make sure that it was worth putting the pistons in unless he absolutely knows the history of the block. They can also mike the block and give him some idea of what style of piston it was bored for originally. Either of the machinists that I deal with wouldn't bore an engine without pistons to fit the bores with so I'd almost bet that the pistons that were to go to the engine found a new home.
No no finish hone on the bores, just oiled and in a bag with a yellow tag on the mains saying .30 over mag good/ mains good. The guy he got it from said the machine work was done in 1998 then sat he bought it then bought the bolt on parts then got hard up and sold/traded to my friend
Like others above posted, get the bores checked for size before you do anything else. If you were in the area, I'd stop over with a dial bore gage and do it for you. No finish-hone marks might be a good thing. I think that you'll get a runner out of the deal once you know what you have there. Bob
Amen. Need to check the bore. Has the block been finished honed with a cross hatch or just the bore job? There is a difference in required piston clearance between, forged and cast pistons. Do the machine shop thing. A few bucks may save more dollars and headaches down the road on the build.
Go to that auction site we all know and love. There are some Grant-100 Forged, 2 valve relief, flat top pistons for $100.00. How do I know? He originally listed them as for a 327, and I bought them. But, the pin height is 1.56, or 350, so they got sent back. The seller did well to me, paid for my shipping to AND back, plus the refund! Now that's standing behind what you sell. Butch/56sedandelivery.
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