350 vs 383
Thread Starter
6th Gear
Joined: Nov 2010
Posts: 6
Likes: 0
From: Hudson MA
350 vs 383
A few questions from a novice; I have 68 Corvette (number matching)327/350HP. With either a M20 or M21 transmission, rear-end I believe is a 3.36/1. I’m planning on removing the 327 (storing it) and replacing it with a 405hp/440TK. 
1. I’m considering the purchase of either a 350 or 383 engine from Summit Racing or DPM Power. I was wondering if anyone has had any experience, good or bad, with either of these vendors and what it was.
2. Will the transmission handle the additional HP and torque or do I need to have it beefed up
3. Same question for the rear-end which I believe is a 3.36/1.
4. Assuming the HP and Torque are about the same, is there really that much difference between a 350 and a 383? If so what is it? I’ve read many comments saying to go with the 383 stroker, However, did not read an explanation ( maybe I missed it) of the reasoning behind it. I admit I’ve not read all the thread on engines
5. Is there another vendor I should look at? (I’ve ruled out CHS Machine Co. in Oregon based on negative comments in the forum)
Thanks for any advice you can give me
Oh yes I forgot one important question, will the 327 exhaust manifold bolt up to the 383 or will I need new manifolds to run to my side pipes ?
Rgards,
Don
1. I’m considering the purchase of either a 350 or 383 engine from Summit Racing or DPM Power. I was wondering if anyone has had any experience, good or bad, with either of these vendors and what it was.
2. Will the transmission handle the additional HP and torque or do I need to have it beefed up
3. Same question for the rear-end which I believe is a 3.36/1.
4. Assuming the HP and Torque are about the same, is there really that much difference between a 350 and a 383? If so what is it? I’ve read many comments saying to go with the 383 stroker, However, did not read an explanation ( maybe I missed it) of the reasoning behind it. I admit I’ve not read all the thread on engines
5. Is there another vendor I should look at? (I’ve ruled out CHS Machine Co. in Oregon based on negative comments in the forum)
Thanks for any advice you can give me
Oh yes I forgot one important question, will the 327 exhaust manifold bolt up to the 383 or will I need new manifolds to run to my side pipes ?
Rgards,
Don
Last edited by Don Lind; Jan 15, 2011 at 11:11 PM.
Burning Brakes
Joined: Oct 2002
Posts: 914
Likes: 14
From: Aberdeen, Scotland
Generally speaking torque is a function of displacement. HP is a function of RPM. So, in very general terms with many other factors equal a 383 will give you an extra 30 ft lbs. Is this an important factor? Up to you .... but torque moves street engines.
Thread Starter
6th Gear
Joined: Nov 2010
Posts: 6
Likes: 0
From: Hudson MA
Do you know of any one in this area I might speak with?
Thanks again.
Last edited by Don Lind; Jan 14, 2011 at 10:04 PM. Reason: Typos
Team Owner
Joined: Oct 2004
Posts: 81,241
Likes: 3,062
From: altered state
St. Jude Donor '05
Youll experience the torque increase at all rpms, youll love it.
It will leave in first better with your trans/rearend gearing and if you choose to lug the motor some it will do it much better than a 350.
For the street its real hard to beat a stroker youll love it.
It may only sound like 30 or so cubes wouldnt make a big difference but its the characteristic OF the power that youll like. I regret building a hot 350 this time around, even as overbuilt as it is a larger ci would feel a lot better.
It will leave in first better with your trans/rearend gearing and if you choose to lug the motor some it will do it much better than a 350.
For the street its real hard to beat a stroker youll love it.
It may only sound like 30 or so cubes wouldnt make a big difference but its the characteristic OF the power that youll like. I regret building a hot 350 this time around, even as overbuilt as it is a larger ci would feel a lot better.
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Drifting
Joined: Aug 2004
Posts: 1,883
Likes: 124
From: Lubbock TX
My son and I built comparable engines at the same time, each dropped into a late 90's Tahoe. He used RHS Vortec heads, I used GM's. I cleaned the bowls and short turns up on mine and just did bowl work on his, they didn't have GM's ridge. Same LT4 cam, same tune. His is a stroker, mine a 350. His truck is a 4-door, mine a 2-door, I'm guessing he outweighs me by 500lbs or so. His truck runs off and leaves mine like I'm tied to a post, the power difference is amazing. Part of it is probably due to the better heads, but that extra stroke/cubes makes more torque, period.
You really should find you a good rebuildable 400, the extra 1/8" of bore makes a bigger difference than you'd think when it comes to optimizing cylinder head breathing.
You really should find you a good rebuildable 400, the extra 1/8" of bore makes a bigger difference than you'd think when it comes to optimizing cylinder head breathing.
Drifting
Joined: Aug 2005
Posts: 1,682
Likes: 3
From: League City TX
4. Assuming the HP and Torque are about the same, is there really that much difference between a 350 and a 383? If so what is it? I’ve read many comments saying to go with the 383 stroker, However, did not read an explanation ( maybe I missed it) of the reasoning behind it. I admit I’ve not read all the thread on engines
But, if the HP & Torque are the same then there is something wrong with your 383.
Extra cubic inches are always a good thing when making power is the goal.
Heel & Toe
Joined: Jun 2010
Posts: 24
Likes: 0
From: San Diego CA
They were also are willing to do any customizing I'd like. They will use a chrome version of the intake for a little extra, or even paint the motor a color scheme of your choosing; you can even send them the paint you'd like them to use.
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
My son and I built comparable engines at the same time, each dropped into a late 90's Tahoe. He used RHS Vortec heads, I used GM's. I cleaned the bowls and short turns up on mine and just did bowl work on his, they didn't have GM's ridge. Same LT4 cam, same tune. His is a stroker, mine a 350. His truck is a 4-door, mine a 2-door, I'm guessing he outweighs me by 500lbs or so. His truck runs off and leaves mine like I'm tied to a post, the power difference is amazing. Part of it is probably due to the better heads, but that extra stroke/cubes makes more torque, period.
You really should find you a good rebuildable 400, the extra 1/8" of bore makes a bigger difference than you'd think when it comes to optimizing cylinder head breathing.
You really should find you a good rebuildable 400, the extra 1/8" of bore makes a bigger difference than you'd think when it comes to optimizing cylinder head breathing.
Is the rear end ratio the same ?
Advanced
Joined: Oct 2009
Posts: 55
Likes: 0
473tq @ 4500 and 443hp @ 5750 could have bumped it up a bit if I dropped the aluminum water pump and went to an electrical one but its about the looks 
Still pondering a turbo or pro charger but that might take away from its looks and advertise to much...
Still pondering a turbo or pro charger but that might take away from its looks and advertise to much...
Melting Slicks
Joined: Mar 2002
Posts: 2,164
Likes: 7
From: Beringen
