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V8 vagueness: to 383 on the cheap or not...


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Just poking around for some ideas. I have a bunch of parts and I'm deciding what to do with them. I'll put this out there for y'all in Z land to ponder and reply...

 

OK, so I have this 350 SBC sitting in my garage, looking mournful as prep the chassis for the V8 conversion. I'll list the rough specs and show you what torture I go through when I visit ebay motors.

 

350 block, bought it from GM Sports Salvage and the engine had been rebuilt.

Mild cam I stabbed in at these specs: Hydraulic Flat Tappet, Adv. Duration 272/ 282, Lift .442/.465. Weiand Stealth manifold, Holly 650 DP, stock heads at what I believe to be 76cc--but I'm not sure.

 

Here is what I have in parts to add: Edelbrock RPM heads with roller rockers (I have 2 sets of aluminum ones and one set of steel rollers). The heads are 62 cc heads which would bump the compression from 8.5:1 to I believe 10.1:1! I'm guessing on the compression ratio increase, but I think I'm close.

 

So what is my dilemma? I see SCAT stroker cranks for sale cheap on ebay that would increase the cc of the motor. I don't have to bore out the cylinders and I'd like to keep the stock rods and pistons for now. What would the compression be with the stoker crank? I would think that I would be relegated to buying race fuel or E-85 to keep the engine running with cylinder pressures approaching 11:1 or more with this "old" engine, but the added cubes for on the cheap sounds pretty tempting.

 

On the other hand, I have a T04E, downpipe, and Turbonetics wastegate from a 500+ hp Grand National and some turbo exhaust manifolds to make it all work. I could turbo the motor with a carb, which would be easiest to do right now, but maybe not the smartest...I'd love to do EFI, but there is no "cheap" way to do it right now and I have nearly all the carb parts. Maybe a MassFlo EFI system like Wayne uses, someday.

 

The transmission is a WC T5, so without planning to drag race it (much), I hope to keep the T5 I have. In the future, a G-Force T5 would be in the works.

 

Just some other specs: 3.9 rear R200 on the car (also have a VLSD Q45 diff too), Eibach lowering springs, Tokiko shocks, urethane bushings, etc.

 

The car would be a "dual purpose" car, for mostly street 'sport' driving (I did not say racing, so don't go there) and maybe some track use. I do not plan on making it a race car. At least not yet, anyway.

 

Given minimal cash outlay, would you do a stroker crank and run special fuel for a mostly street car, or would you stick with the 350 and call it good?

 

Keep in mind that the idea is MINIMAL cash outlay. I can build a proper 383 in the future when the time comes, but I won't go half way with that...

 

Davy

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That is the thing I'm talking about. The question is whether or not to do it. I know the stoker crank will increase torque and hp, but it changes some things for me and I'm trying to make sense of it all... *head hurts*

 

The simplest thing to do is to retain the 350 with the Edelbrock heads, don't turbo it and run it like that.

 

If time & money were no object and I was staying with the Gen I motors, I would build a low compression 383 with forged parts, H-beam rods, the works and then turbo the sucker. That would be fun, but I have the parts I have to work with and not much more. I want to avoid any more large cash outlays as possible.

 

Davy

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If you buy a 383 crank, you will need pistons to match. You could use the same rods.

 

I would build the 350. A 383 is a great motor, but a nice 350 in a Z can be pretty much a terror. I'll be glad to help out if needed.

 

When you get it running, bring it down to CMP and I'll help you get it sorted out.

 

 

John

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If you have E85 available in your area, that might be a good path to go down. The fuel system would have to be upgraded, but what I have read on the octane rating of E85, somewhere in the range of 100-105, gives lots of opportunity. Higher compression n/a or a nice turbo setup, good to go either way.

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If you buy a 383 crank, you will need pistons to match. You could use the same rods.

That would pretty much decide it then. I just don't want to keep spending on what amounts to a half-build in my opinion. If I have to do pistons too, then I might as well do rods, etc, for a proper build. I can't (and shouldn't) do that yet at this stage.

 

I would build the 350. A 383 is a great motor' date=' but a nice 350 in a Z can be pretty much a terror. I'll be glad to help out if needed. When you get it running, bring it down to CMP and I'll help you get it sorted out.

 

John[/quote']

 

Wow, that's an offer I just can't refuse! THANK YOU! I'm still getting the engine compartment set to do the conversion and the idea is to paint it first, etc, then stab in the motor. I'll certainly take you up on your offer, belated of course.

 

Davy

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If you have E85 available in your area, that might be a good path to go down. The fuel system would have to be upgraded, but what I have read on the octane rating of E85, somewhere in the range of 100-105, gives lots of opportunity. Higher compression n/a or a nice turbo setup, good to go either way.

 

That's the one thing that keeps my interest on a relatively high compression turbo set up. I have an E-85 station about 10 miles from my house, so it is attainable. A road trip might be out of the question, but hey, I'm willing to try it :D I wanted to run aluminum fuel lines, etc, but I'll have to change my thinking if I go the E-85 route. It's not that it can't be done, it's just a little harder and more expensive to do (which means I can't do it yet).

 

Davy

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I am doing a 383 myself. The parts, overall, are not expensive. Its a swap that has been done over and over and is tried an true. The LS swap would be reeaaly nice, but fuel injection adds cost and complexity. It may end up being about the same price as a used LS swap, but a carb set-up reduces wiring issue problems. Super Chevy did a 383 build earlier this year and got about 425 hp out of the engine. I already planned to use the same heads they did. The cam may end up being a bit more mild then theirs. I wont be racing it on a strip other than to see what it will do, so all out hp is not my goal. Just a good driving car with a strong engine is all I need/want. I think an old fashioned 383 will fit the bill just fine.

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The biggest problem with a 383 in a Z is the balancer and flywheel. In most cases a 6 inch balancer and and 153 tool flywheel will be require for clearance reasons, especially if you use a T5 which needs the engine set back (JTR position). And most 383's are externally balanced which requires a counter weighted balancer and flywheel, and most all of those are 8 inch and 168 tooth versions. The simple fix is to use an internally balanced 383 kit, but it cost more. In any case, add in the cost of counter weighted end parts or internal balancing.

 

A 350 with a good set of heads will run better than a 383 with stock heads. So spend the money on heads first, then on stroke.

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A 350 with a good set of heads will run better than a 383 with stock heads. So spend the money on heads first, then on stroke.

 

I agree...

 

Here is what I have in parts to add: Edelbrock RPM heads with roller rockers (I have 2 sets of aluminum ones and one set of steel rollers). The heads are 62 cc heads which would bump the compression from 8.5:1 to what I believe 10.1:1! I'm guessing on the compression ratio increase, but I think I'm close...

 

I already have some decent heads; they may not be the all out best, but for the price I bought these baby's for, NO ONE would have walked away from them ;) . I agree about the balancing issues in a 383, but please understand that an internally balanced crank is the same price on ebay as an externally balanced one. There is no way I would build an externally balanced 383 for a 240Z, when I know that an 8" damper won't fit. I have a nice properly fitting Fluidamper that I'm dying to use when the time comes; also bought that cheap at someone's "fire sale."

 

 

Davy

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