Does anyone know the HP/FTlbs difference between these engines in stock form? Built up? Also I read that the 377 revs higher and faster than the 383.. How much is the difference there?
Just looking around at a few engine optoins here Ultimately my dream is to build up one of these sbc's, turbo it, add a lim slip diff then go out and cook some nice cars for 35 mins at 350Celcius or untill golden brown.

quote Originally posted by Sloth_Pilot: Does anyone know the HP/FTlbs difference between these engines in stock form? Built up? Also I read that the 377 revs higher and faster than the 383.. How much is the difference there? Just looking around at a few engine optoins here Ultimately my dream is to build up one of these sbc's, turbo it, add a lim slip diff then go out and cook some nice cars for 35 mins at 350Celcius or untill golden brown.

The problem is that there are no stock 377s or 383s.

I suppose if both engines were built similarly, the 383 would edge out the 377 in torque, plus put it out a lot earlier. However, the 377 would be superior in top end HP as well as would like to rev more than the 383.

If you are going to throw boost at this engine in the future, I strongly suggest that you go with the destroked 377. It will be more efficient and spread the power out more evenly across the RPM band compared to the 383. One thing you need to watch is cylinder wall thickness. I would not push serious boost on any engine that has been bored more than .030" over; depending on wall-thickness. Most machine shops have charts on what a typical cylinder wall thickness should be for power and boost levels. They are different between boosted and non boosted engines. Good luck with your project.

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1987 Pontiac Fiero Coupe #18,838
3800 Series II SFI; 4T60-E Trans w/ 3.33 final drive; Terminator exhaust; 4 wheel vented disc conversion; Walbro 307 fuel pump; W-body air box w/ K&N filter; Rear 32mm sway bar; 134a functioning A/C; GM Pontiac CD player 7-band EQ w/ factory location sub; much more and...a stock GN's TURBO on the way!

Conversions Performed:

1985 SE 3800 Series 1 SC 4T60-E
1987 Coupe 3800 Series II 4T60-E
1987 SE 3.4 TDC 5-speed

http://dtcc.cz28.com

[This message has been edited by Darth Fiero (edited 01-04-2003).]

darth hit it pretty much on the head. but to stroke or to destroke depends on the related components. its "COMBINATION" that makes it fast not h.p. or torque. you can have a 450h.p motor with 500 ft pound of torque and still get your arse kicked. what trans and gear ratio, tire size and total car weight all are factors that need to be addressed along with or before engine design. address these issues first, then ........

I had always wanted to build a 383. Thought it would be a blast to drive around on the street. One of my friends asked me why I wanted to go to the trouble of making a hybrid engine when it would be so easy to just go with a 400. I don't know what I was thinking.

Dave

You do NOT want to use a 400 with the 400 crank. The 400 crank is abysmally weak. it's also an unbalanced design and to get it to be internally balanced takes cubic $$$.

The trade off is simple. Ideally, the 377 has the best bore/stroke relationship next to the old 302 Z/28 engine. It's also very close to an ideal rod length/stroke relationship.

All of the above is really only vitally important in a real race engine, but if you're going to go to the trouble, it does pay to do it right.

To use the 350 crank in the 400 block, you have to use special main bearings and they are fairly high dollar compared to stock 350 bearings. I've built maybe a dozen of these up for the circle burners in years past as well as a few for boats (my own jet boat had one), and they can put out impressive numbers. But the best bang for the buck is still the 350 based block IMHO.

John Stricker

quote Originally posted by dgroves: I had always wanted to build a 383. Thought it would be a blast to drive around on the street. One of my friends asked me why I wanted to go to the trouble of making a hybrid engine when it would be so easy to just go with a 400. I don't know what I was thinking. Dave

If you want to build a really cool engine, I'd suggest this one: http://www.airflowresearch.com/articles/article03/A3-P1.htm

For street use, the 400 crank in a 400 block is fine. It's a little more problematic when you turn the mains down to put it in a 350 block, but if you're doing that, just buy an aftermarket crank.

The 400 mains are larger than the 350 mains to maintain "overlap" between the main journals and the rod journals.

When it's all said and done, there is very little performance difference between a 383 and 377. The small amount of better reving capability of the 377 is only really achieved if you use expensive light weight racing pistons and high dollar valve train components. Then you still have a crappy siamesed bore 400 block that is prone to overheating, especially when bored out. For the average Joe Blow who don't wanna spend a fortune, the 383 is a better choice. Then you can use a cheap and plentiful 4 bolt main 350 block and get a good aftermarket forged crank/forged piston stroker kit. Of course, you can still build a red hot 350 a lot cheaper and really are only sacrificing a little torque. How much torque do you need above and beyond a 350 in a Fiero anyway? But yeah, those 383 motors are very sweet.

[This message has been edited by batboy (edited 01-05-2003).]

377 ALL the way, Fieros need revy motors, not RV lumps.

SBC engine combos have been posted here, recently, by Will. Do a search, I'd recomend the most 'oversquare' you can get (short-stroke, large bore. Rev monster, FUN FUN FUN.

Best!
Ben.

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Ben Cannon
88 Formula, T-top, Metalic Red. (2:13.138 at Sears Point) "Every Man Dies, not every man really Lives"
88 Formula, Northstar, Silver, In-Progreess. -Mel Gibson, "Braveheart"