Hello!
I have spent many hours searching through the forums to find answers to a few questions I have regarding my motor swap. I have found answers to a few of them, but I still need a little clarification on some aspects. I have a 1984 Trans Am, originally a L69 305 HO with a 5-speed and no t-tops. I have pulled the 305 and am planning to build a 383 for the car. I have the 350 4-bolt block already, and have the machine work done to the block. First, is it unreasonable to hope to get between 400 and 500 hp out of a 383 with compression between 9.5 and 10:1? I was thinking cast crank (but will go forged if people think it'll be necessary, I might want to drop a 100 hp nitrous kit on it sometime down the road), h-beam rods, and I'm not sure on pistons quite yet and am open to suggestions. I'd like to buy a complete kit (possibly from powerhouse) that'll be already balanced and ready to put together (this'll be my first engine build) I am also undecided on a cam as I really don't have much experience with or knowledge of cam profiles, but I am pretty sure I want roller lifters and rockers. Also, I am figuring on 2.02I/1.6E in the heads, but I don't know if I should go with chevy heads, or get Edelbrocks or what?? Ok, I think that about does it for the engine, any suggestions would be greatly appreciated!
Now, can I get away with running my stock size bellhousing with the small flywheel and a 10.5 inch clutch, or do I really have to get a different bellhousing, new bigger flywheel and an 11 inch clutch? I've heard (from the guy I talked to at Summit) that if I'm putting that much power in my car I'll bend the car before a 10.5 inch clutch will slip...I'm thinking that might be bogus (bending the car anyway) but I dunno. Also, he said that Centerforce Dual Friction clutches are junk, and that they were "good in their day" whatever that means...I've been impressed with the Centerforce stuff, what about you folks? Oh, I am planning on running subframe connectors on the car, just so ya know (bolt on or weld??)
Ok, now for exhaust! this is the fun part! j/k Can I get a set of headers that'll clear my stock slave cylinder mount? The ones that were on my car when I got it had required the previous owner to "modify" the slave cylinder mount which did not help clutch operation to say the least. I REALLY REALLY want to run true dual 3" pipes with a crossover/h-pipe (I've done lots of searching on this topic) and I really want to know if this is possible or worth it...should I just run a really big single, bigger than stock(obviously)?
I'm sorry this is so long, but I really appreciate anyone who can help me out....I'm really looking forward to kicking some Mustang butt with this car, but if its just gonna bend in half like the guy at Summit who's "owned 3 or 4 of those cars" said it will, should I really bother to build up an engine that much?? Thanks for any help you can give me!!

Paul

 

Even the littlest bit of help would be most appreciated!

Thanks!

Paul

 

This will all be second-hand info. But, here goes anyway.

You've machined the block without the pistons? I hope you're only talking about the pan rail clearancing, not the boring and honing. Your HP goals are reasonable with a 383. Go forged if you can swing it.

Only way I've heard of being able to use smaller flywheels is to have the crank internally balanced. More expensive, but solves other problems as well. Like starter.

They're right about bending the car if you don't have the SFC's. But, you're taking care of that.

That's all I'll try. Somebody else can take a shot at the rest.

 

Thanks Five7kid,
Yea, the boring and honing is done on the block, but it was a stock block and I just got it bored .030 over, so I'm just planning on getting .030 over pistons for it. Did I miss something? I didn't know that you had to have the pistons before you bored if you were going with a standard overbore.
Thanks again, and I hope to hear from others on my questions too!

Thanks!

Paul

 

There are tolerances in the piston dimensions, even if they are all called '.030"-over' pistons. The smart practice is to do the final honing so the proper skirt to cylinder clearance can be matched to the pistons you're going to put in (type of piston will also affect that). That's all. I've never seen a shop that would do it without the pistons in hand (at least one piston, anyway - dimensions are usually pretty close in a given set).

 

Thanks again Five7kid,
I'm not sure if the shop did the final hone or not, I don't think so, but I'm gonna check...in any case what's done is done, and I'll see what happens from here On my exhaust question, do folks think that the flowmaster system that 87 B4Z has for sale would flow enough for my motor? (it's for sale Here on the Exhaust board ) Because then I could go with say an SLP or Edelbrock header setup with a stock type y pipe and wouldn't have to worry about header clearance. Should I go that route, or stick with true duals?

Thanks for any and all help!

Paul

 

Any other thoughts?

 

Anything at all?

 

Ok, maybe someone can help me with this. I called Powerhouse (engine parts company in California) to order my 383 kit. I told them I needed the small (153 tooth) flywheel and they told me that they can't balance the kit with a small flywheel, only the big one. This is because the 383 crank is a 400 crank and is supposed to be externally balanced and I guess you'd hafta put a pretty huge weight on the small flywheel to get it balanced right. So, I am thinking that I might go ahead and build a real strong 350 instead. I'd still like to stay around 9.5:1 CR but I'd like to get maybe 400 HP or a little more, is this reasonable? What do you guys suggest for parts. I am going to go with forged pistons and h-beam rods, but beyond that does anyone have any suggestions?

Thanks!

Paul

 

It'll be tough to get 400HP out of a 305, but it is possible. I've seen it done on a ford, so it can be done on a chevy. The guy at Summit that you talked to must be a fool if he says that the dual friction clutch is junk. I havent broken my clutch in yet, but ive talked to many mechanics and car enthusiasts who've seen dual frictions take a beating, and they're still perfectly fine. And ive never heard of a broken dual friction clutch before, so id suggest it if you need a new clutch.

 

I read in a magazine that the Centerforce would over power the seals in the slave clyinder and resulted in having to force the car in and out of gear. This was on a T56...


Also, go with the weld in SFC's,boltins arent even worth the time or money.

 

Thanks a bunch guys!

Any thoughts from others?

 

There are those bolt-on balance plates, but I a) don't know if they work with 153-tooth flywheel, and b) don't know of anyone who has used one.
400 HP out of a 350 isn't unreasonable, still steetable.