383 build for Scout

Hi guys, new guy here. I am building a 383 to replace the 345 IHC motor in my Scout, I have a adapter kit from Advance Adapter's that makes it possible to bolt a SBC to the IHC transmission using a adapter plate.
I have to use a two piece seal block because it uses a std 350 flexplate, I have a Scat externally balanced crank, I plan to use one of those counterweight plates the gets sandwiched the crank and flexplate but I plan to use it on torque converter side because there are spacers so there is plenty of room for the counterweight plate, I also plan to weld it to the flexplate. I plan to use a externally balanced damper. This is going to be a torque motor that will never see any thing past 5000 RPM, I have a set of brand new "Swirl Port" heads, I know they are not the best head for performance but should make good low rpm torque. I need to find a cam to match what I am building, any recommendations? I have more ?s but I will save them for later. Thanks for any help.

Casey

Welcome aboard, good to see you here and it sounds like an interesting project. Others can recommend a cam perhaps, I'd suggest finding a cam manufacturer you like and talk with their tech folks and let them guide you.

sounds like you may have a mis match of parts-------caution area----a external balanced crank-probably is for a one piece seal block? if so , the bolt pattern to end of crank is different than the internal 350s are-------------if it is just external balance and has the early bolt pattern, use a 400 sbc or 454flex plate--its external and right bolt pattern---------if you use one of those spacer bobs-and weld on it, you will change the weight by about a gram per inch of welding rod.


so please clarify what you have with some part numbers and pics

When I built my last 383 I called Comp cams and got their recommendations
as to what I was after. Ended up with roller cam and lifters as well as bigger
springs for heads etc. Came as a Kit I believe.

Quote:

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Originally Posted by rdobbs

When I built my last 383 I called Comp cams and got their recommendations
as to what I was after. Ended up with roller cam and lifters as well as bigger
springs for heads etc. Came as a Kit I believe.

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Good advice! Another thought is to have your rotating assembly dynamically balanced once you have everything ready, especially if you do any welding on any piece., IMO.

duplicate post.

For a 5000 rpm motor, I would recommend a 9.00:1 to 9.25:1 static compression ratio, matched with a cam that has 208 to 213 degrees intake duration at 0.050" tappet lift and operates from 1,000-5,000 rpm's. Here's an example of what I might use.....
http://www.summitracing.com/parts/hr...5-10/overview/
Howards, Hyd. Roller Cam & Lifter Kit, Chev SB, Retro-Fit - Competition Products
More cam than this will require more static compression ratio and will raise the operating rpm range beyond the ability of your heads to fill the cylinders.

.

Quote:

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Originally Posted by jerry clayton

sounds like you may have a mis match of parts-------caution area----a external balanced crank-probably is for a one piece seal block? if so , the bolt pattern to end of crank is different than the internal 350s are-------------if it is just external balance and has the early bolt pattern, use a 400 sbc or 454flex plate--its external and right bolt pattern---------if you use one of those spacer bobs-and weld on it, you will change the weight by about a gram per inch of welding rod.


so please clarify what you have with some part numbers and pics

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Jerry
It is defiantly a 2P style crank, I cant use a ext balanced flexplate because the weights are in the way of the spacers that attach it to a IHC converter, It uses a stock Chevy flex plate that has been redrilled for the IHC converter, there are 4 spacers that make up the thickness of the adapter plate between the motor and the trans, there is also a spacer that fits in the back of the crank to center the converter. I wish I could use a 1P seal block, the internal motor already leaks enough oil, I wish I could do a full Chevy motor/trans swap but then I would have to make new drive shafts, trans mounts and a lot of other things and I am not sure the if the transfer case is on the same side as my Scout. I will try to get some pictures up as soon as I can.

Casey

techinspector1
That looks like a pretty good deal, I would like to go with a Hyd roller cam.

I am looking at rods for this build, I am going to use 5.7's with a bushed pin and some thing that I don't have to bushwhack the block too much so they don't hit. I had thought about having a set of stock rods rebuilt and bushed but I can probably get new ones for not much more. Next, Pistons

Casey

a one piece real seal block would probably be a better deal as you could take advantage of the roller lifter setup---------you'd just need an adapter for using the 2 pc seal crank and oil pan---

Agree with Jerry. What's the casting number on your heads? I'll help you find pistons if I can figure the static compression ratio and to do that I need the chamber volume.

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Tech
the head casting # is 14102193, They are a center bolt valve cover style head. they are unmodified NOS heads, they have a large combustion chamber but I don't have any way to measure them right now.
I was thinking about using these...
http://www.amazon.com/Chevy-Flat-Pis.../dp/B00D9T5Q2G
I know Amazon is probably not the best place to buy pistons but the price seems pretty good.
I will look into the late model block with adapter, it would be nice to use the stock roller cam parts instead of retro fit kits.

Casey

As long as we are talking heads, I have a brand new Edelbrock Performer intake [part # 2101] that I got before I got the later model heads [I got a great deal on the manifold, thanks Craigslist] I have heard that I can make it fit if I make some wedge shaped washers for the center bolts, I know it sound like I am being cheap on this build but I am disabled and only make about a third what I used to and you have to cut me a break, I have been wrenching on VW's for the last 20 years and still do.

Casey

Casey-----------if you can't find the adapter for the 2 pc deal for late block-----I probably still have 15 - 20 of them around here that are billet alum pieces make by K teck back in the IROC days-----------

Quote:

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Originally Posted by Earthquake

Tech
the head casting # is 14102193, They are a center bolt valve cover style head. they are unmodified NOS heads, they have a large combustion chamber but I don't have any way to measure them right now.
I was thinking about using these...
http://www.amazon.com/Chevy-Flat-Pis.../dp/B00D9T5Q2G
I know Amazon is probably not the best place to buy pistons but the price seems pretty good.
I will look into the late model block with adapter, it would be nice to use the stock roller cam parts instead of retro fit kits.
Casey

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Casey, the heads are 65.3cc chambers. You would need a 24cc piston dish to lower the SCR to ~9.0:1. The flat-top you linked would put the SCR at 11.00:1, way, way too much for iron heads and pump gas and you'd have to use a cam that operates between 3200 and 7000. The cam would just be coming on as the heads were signing off. Bad idea. Get rid of the heads, no matter how little money you have in them. Invest in a set of Pro-Filer 185's (70cc chambers) (under $1100) and a set of 18cc dished pistons to arrive at a ~9.20:1 SCR. Then install a cam with an intake duration of 204-210 degrees @0.050" tappet lift.

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I would have thought those chambers were bigger then that, they look bigger.
So what about this set of pistons...
http://www.summitracing.com/parts/stl-h890cp30

Let me list what parts I have so far...
"010" 2 bolt block
"14102193' heads
Edelbrock Performer [2101]
Scat Crank 9-350-3750-5700
Rods TBD [5.7 bushed pin]
pistons SP H890CP30's?
Cam TBD [roller would be a +]
Mag. Corvette Center bolt valve covers
Edelbrock 600 cfm carb
Stainless "block hugger" headers [2" off the collectors into a single 3" out the back]

I know I need a lot more but I am trying to collect it a little at a time. I also know the heads are going to be a limiting factor but I would really like to use them, I will be looking for some thing better once I get it back on the road.

Casey

Quote:

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Originally Posted by Earthquake

So what about this set of pistons...
http://www.summitracing.com/parts/stl-h890cp30
Casey

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Yep, those will work. I'd use something like a 110315-10 Howards retro hydraulic roller cam with 91164N Howards hydraulic roller tappets.
You can order the cam from Howards with a reduced base circle to clear the 5.7 rods, or you can use a full base circle cam and Scat 25700P rods. You can also use stock Chevy rods and grind some material off at or near the bolt head to clear the cam lobes, but I don't advise grinding on rods.
http://www.summitracing.com/parts/sca-25700p/overview/
http://www.summitracing.com/parts/hrs-91164n/overview/
http://www.summitracing.com/parts/hr...5-10/overview/
These springs would work.....
http://www.summitracing.com/parts/hrs-98212/overview/
Estimate SCR at 9.2:1, DCR at 8.33:1
Use a steel shim gasket to set the squish between 0.035" and 0.045". Gasket thickness added to piston deck height equals squish.

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How about these pistons...
Sealed Power H859CP30 Speed-Pro Hypereutectic Pistons with Coated Skirt - Free Shipping on All Orders @ JEGS
There a bit cheaper and they list the comp ratio at 9.6 to 1 with 64cc chambers?

I have a block question, would it be worth it to me to use studs on the mains of the "010" block [2 bolt main] for this build or just bolts? Like I said I will not be spinning this motor very high RPM's, I am buying new main and head bolts regardless so a set of stud for the bottom end is not a big deal, I am using bolts on the heads in case I ever have to change a head gasket or come up with a nice set of heads.
Thanks for the help guys!

Casey

I put studs thru-out on my 383 when I built it. Was about 475 HP and I gave
it h#ll. Don't think I really needed the studs at this HP, but I went with them
anyway. You should be ok with just good bolts.