|06-26-2013 05:07 PM|
|06-26-2013 03:23 PM|
I have a 383 in the works with similar parts(Scat stroker crank,Mahle flat tops, Scat 6" rods).
I have Alum heads that have about 72cc chambers, and with the flat tops 5cc, and with a .039 squish I get about 10.3:1 static CR. Looking to get a roller cam with about 270-276 adv. duration to get less than 8.5:1 dynamic CR for pump gas on the street. IMO if you get 64cc heads your CR is going to be too high for pump gas, and you'll regret it.
If your pistons have the same 5cc reliefs mine do, I'd get some heads with at least 72cc chambers if you plan to use a stock convertor auto trans on the street.
Also I heard some bad things about the Professional Products dampners (after I bought mine of course). The timing numbers are painted on and I wouldn't expect them to be very visible for more than a few years before they seccumb to the elements. IMO, and many others, Powerbond makes a better dampner, but you can't get it from Summit if I'm not mistaken. I got mine from O'Reilly Auto Parts. The numbers are engraved, and painted. If they get indescernible you can fill them back up with paint with a little effort. Also supposed to have a better elastomer bond.
I also have the Air Gap manifold, but welded up the plenum divider notch in hope of smoother idle and better off idle instantaneous throttle response. Keeping fingers crossed. I would probally have bought the regular RPM instead of Air Gap had I known that it had a notch beforehand.
Using a Felpro 1010 Head gasket w/copper combustion ring for Alum. heads. Ported intakes to match a Felpro 1205, exhaust to mate with a Felpro 1406, and Tri-Y headers.
Using a 750 Holley with a 1/4" 4-hole insulator/gasket/adapter. The adapter is mainly because I couldn't get a manifold vacuum fitting to fit under the Holley without one.
I'm hoping for about 425-450hp and 475ftlbs of torque. It looks as if your going for more horsepower than torque like me, but keep us posted as to how things turn out. I for one am very interested.
|06-25-2013 10:51 PM|
Take care Richard...
|06-25-2013 10:45 PM|
|06-25-2013 10:34 PM|
I know it ain't gonna change, and we all learn by our mistakes and by experience , hell , I did some stupid things when I was green, back when., put a negative overlap cam (low down 'stump puller) ' into a 12.5:1 engine and wound up with 275psi cylinder pressures , couldn't get the ping out of it , even on methanol , LOL! so I really shouldn't criticize , ha ha!!
We all live and learn...
|06-25-2013 10:30 PM|
|SGreve32x||Well, Just spent a small bundle on parts tonight. Bought a Scat Forged 4340 crank, Mahle flattop alum forged pistons, clevite bearings, and scat forged 6" rods. The heads I am looking at are Brodix heads with 180cc intake ports with 64 cc combustion chambers.|
|06-25-2013 09:41 PM|
350 uses 1.560" piston, 5.7" rod and 1.740" crank radius for a stack of 9.000".
383 uses 1.425" piston, 5.7" rod and 1.875" crank radius for a stack of 9.000".
What you are doing is using a shorter piston to make up for the increased stroke radius, so that you keep the "stack" within the confines of the block deck height.
Same with any small block....
327 uses 1.675" piston, 5.7" rod and 1.625" crank radius for a stack of 9.000"
283 uses 1.800" piston, 5.7" rod and 1.500" crank radius for a stack of 9.000"
Putting a "stack" together has little to do with reducing cylinder sidewall pressure. It simply entails fitting the proper "stack" of parts into the available space.
Here's an example of a D-Cup hypereutectic piston from Keith Black. See the large, flat pad on the piston crown in the left of the photo? That's what Big Ed is talking about when he says that you need a flat area to mate with the underside of the head to form the squish.
|06-25-2013 09:39 PM|
|BigEd36||SGreve32x, are you planning on this 383 being a pump gas engine? The Skip White kit you've listed with flat top pistons will give a too high static compression ratio to run on pump gas unless you go with 72 or 76cc chambered heads, which will limit your choices in heads. Built with a deck height/head gasket combo that gives a .040" quench your static CR will be 11.25:1, too high for pump gas. With a 72 cc chamber head the static CR will be 10.28:1 (still pretty high but could be ok with a tight quench), with a 76 cc chamber head the static CR will be 9.86:1. Using 64cc heads gives you a much greater choice in heads, but you'll need a dished piston to keep the CR in line if you want to run pump gas. The problem is the Probe dished pistons have a round dish which doesn't give a good quench. It would be MUCH better to have a D dish/reverse dome/step dish type of piston that aren't available in the Probe FPS series included in the Skip White kits.|
|06-25-2013 08:52 PM|
|65Xchevy II||I have the same kit, but purchased from summit racing for the same price. The pieces were actually shipped from scat after they do a static balance on the assembly. It came with KB pistons,( hyperutetic) and moly rings. Had the machine work done locally to the block, when it was all assembled I had no clearance issues. I would purchase it from summit you get to pick the CC of the piston you want. I got +13 CC pistons to go with my 62 CC heads I have 10:1 CR. Don't forget this piston will travel an additional 1/8 inch in the cylinder both directions leaving you with a deck clearance of .016 compared to a normal 350 of. 125. This will have a big impact when calculating you compression ratio. Make sure the piston has a compression height of 1.43, this raises your wrist pin on in the piston to reduce the cylinder sidewall pressure and keeps your piston below your deck.|
|06-25-2013 08:15 PM|
Most kits have a inherent low dollar parts element incorporated into them in order to achieve the selling price.It was the single most reason why I mixed parts to make up my 383.I spent the money on parts that I thought where over built and important to me like a Howards crank and the other parts that I thought where a good buy for the money like the Scat clearance ARP rods and I-Con pistons with forged tops and off-set pins to limit cold piston slap.Then bought Kings bearings which are a class act in every way.No performance advantage to full floater piston pins which has the potential of more things going wrong and over time wearing out the bushings so I went with press fit pins.
I agree with everyone else that all too often we see guys build 383's and when they get to the heads try to cheap out leaving way too much on the table.Guys get tangled up in what street cars should use vs what the correct combo for a drag race engine should use.In a race application you do want to tailor raise the power curve in the rpm range,but in a street engine it is a simple honest question of how many times are you going to be able to use that raised RPM in the course of a yr and get to use the money spent?? Torque is king on the street and not necessary HP.The 195cc intake runner is just about right for a street 383 or just about a 200 cc runner.You start getting around the 220 runner size and lose some of the bottom or need a looser T/C to take a advantage of it.
Do limit the SCR with steel heads to 9.5 or with aluminum heads 10.5 and a DCR of 8.5.In ther long run your be glad you did.
|06-25-2013 07:23 PM|
|06-25-2013 04:08 PM|
|SGreve32x||Well thanks for you input guys.|
|06-25-2013 03:53 PM|
|06-25-2013 03:52 PM|
Valve Lift @ 1.5:1
this cam? 5600 RPM in a 350?
|06-25-2013 03:49 PM|
|vinniekq2||all cams are good or bad,they have to match the application.Buying a cam before the heads is just plain wrong|
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