New Engine?
Thread Starter
Racer
Joined: Jan 2007
Posts: 253
Likes: 0
From: Winter Haven Florida
New Engine?
Hey guys,
This is my first post in here about my 75 L48 vette. I am contemplating what to do here. I want to upgrade my engine but am not sure which way to go. I rebuilt from Cam up through Carb with new Cam, Valves, Springs, Lifters, Intake, Carb, and distributor. Most from Edelbrock. It runs nice, but just not enough for me. I was considering taking the engine out and having it machined for 383 rebuild, but then considered just building a 454 from scratch. Not sure which way would be the best as far as performance and driveability are concerned. I will have the machine work done, but will assemble, install, and remove the engine(s) myself. I want to do that part(main reason I'm doing this). I will have it tuned at RevExtreme over in Tampa after I'm done(they did my 02 Z and I'm really impressed).
Any advice, suggestions, questions?
Josh
This is my first post in here about my 75 L48 vette. I am contemplating what to do here. I want to upgrade my engine but am not sure which way to go. I rebuilt from Cam up through Carb with new Cam, Valves, Springs, Lifters, Intake, Carb, and distributor. Most from Edelbrock. It runs nice, but just not enough for me. I was considering taking the engine out and having it machined for 383 rebuild, but then considered just building a 454 from scratch. Not sure which way would be the best as far as performance and driveability are concerned. I will have the machine work done, but will assemble, install, and remove the engine(s) myself. I want to do that part(main reason I'm doing this). I will have it tuned at RevExtreme over in Tampa after I'm done(they did my 02 Z and I'm really impressed).
Any advice, suggestions, questions?
Josh
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Basically you have the same "problem" that I had..... you already have good heads, intake , carb and headers (??) for a small block...
A big block would require many new parts - a 383 or a 396 small block is the least expensive way to go.
The next question is : old or new block, buy a machined block or have the old block machined.....
I chose to buy a machined block, $700 gets you a good block, .030" over 1pc or 2pc RMS (I opted for the roller cam block).
The shop offered an assembled short block for not much more than I would have paid for the parts anyways so I let them assemble it and ship it as an assembly.
I found that local machine shops are very expensive, two shops quoted me $550-$700 to machine my old block
A big block would require many new parts - a 383 or a 396 small block is the least expensive way to go.
The next question is : old or new block, buy a machined block or have the old block machined.....
I chose to buy a machined block, $700 gets you a good block, .030" over 1pc or 2pc RMS (I opted for the roller cam block).
The shop offered an assembled short block for not much more than I would have paid for the parts anyways so I let them assemble it and ship it as an assembly.
I found that local machine shops are very expensive, two shops quoted me $550-$700 to machine my old block
Thread Starter
Racer
Joined: Jan 2007
Posts: 253
Likes: 0
From: Winter Haven Florida
I think your right man. I will stick with the original block and get it machined for bigger pistons and/or rods. Everything will be forged. The heads aren't new. They are the stock heads with all new parts. They weren't machined or anything. Will this be a problem. Know anything about the Camel Hump heads? What kind of increase in power will this give me? any idea?
Thanks,
Josh
Thanks,
Josh
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
Machining your block will be as expensive as a machined used block - if there's nothing wrong with the block that you have I'd leave it alone.
I thought you already have good heads, that's why I said stick with a small block.
If you have to buy aluminum heads anyways then I'd consider a big block.
Or you go the cheaper route and only buy aluminum heads and leave the bottom end alone. The stock heads are very restrictive - a stock bottom end with a nice cam, alu heads and headers is not bad at all
It depends on what you want and how much you want to spend.....
I thought you already have good heads, that's why I said stick with a small block.
If you have to buy aluminum heads anyways then I'd consider a big block.
Or you go the cheaper route and only buy aluminum heads and leave the bottom end alone. The stock heads are very restrictive - a stock bottom end with a nice cam, alu heads and headers is not bad at all
It depends on what you want and how much you want to spend.....
Melting Slicks
Joined: May 2006
Posts: 3,438
Likes: 41
From: Raleigh NC
St. Jude Donor '13-'14
Alot of these guys are gonna wanna know exactly what you're looking for out of your 75. The first thing they will all tell you though, regardless of your application, is get new heads. I was personally in this decision making process about a month ago when after a lengthy discussion was convinced to stick with the old 350 block, upgrade the heads, slap on some headers and some other minor bold on replacements, and you're looking at around 440HP.
Here's the thread of my discussion http://forums.corvetteforum.com/show....php?t=1593880
Here's the thread of my discussion http://forums.corvetteforum.com/show....php?t=1593880
NCM Grand Opening Veteran
Joined: Sep 2005
Posts: 20,979
Likes: 384
From: South of giving a damn
St. Jude Donor '11, '17
SBC parts are cheaper (somewhat) & more plentiful than BBC parts. If you cahnge a BB then you need wiring, brackets, springs, etc for a BB. Stay with the SB unless you have really weighted the options & want the BB. The iron heads you have are barely good enough for a 350, if you want to use them on a 383 or 396, then don't bother changing your engine or spending any money. Go 396, as 383 are a dime a dozen. Decide on your CI, power desired etc, then chose the heads to match the other components. Or, if you are really brave then wait for AFR Eliminator 220s & then build the engine to support the heads.
Thread Starter
Racer
Joined: Jan 2007
Posts: 253
Likes: 0
From: Winter Haven Florida
First things first. I have an original 1975 350 sbc. I've upgraded/replaced the cam, springs, lifters, valves, intake, carb, distributor and have headers. I'm not sure when the engine was rebuilt, if it even was. I didn't know I could get 396 out of this block, thanks for the suggestions. Is that going to be able to produce more torque than a 383? I want atleast 350RWHP out of this car. I was thinking about some vortech heads, but don't want to buy a new intake and carb, so some aluminum heads would probably do the trick. I can just put what I have in my heads now in them. I'm restoring this car, so I want to start at the engine and not have to come back later.
Le Mans Master
Joined: Oct 2004
Posts: 5,269
Likes: 54
From: Orlando Florida
St. Jude Donor '05
You can get a 383 ci short block assembled for $1500 on Ebay, there are several machine shops with good reputation that sell on Ebay. Of course, there are several backyard mechanics trying to sell their junk on Ebay.... make sure you check feedback and see if that business has their own website (outside of Ebay)... email others who have bought engines from that seller and so on...
I bought from MandRengines and they were good to deal with, another ebay shop is "theenginestore".... both sell short blocks for around $1500 or $2000-2300 with forged internals.
You can barely buy the parts and have your block machined for that much... and you still have to assemble it....
You'll need aluminum heads no matter what - maybe they cut you a deal if you buy those from the same place......
I bought from MandRengines and they were good to deal with, another ebay shop is "theenginestore".... both sell short blocks for around $1500 or $2000-2300 with forged internals.
You can barely buy the parts and have your block machined for that much... and you still have to assemble it....
You'll need aluminum heads no matter what - maybe they cut you a deal if you buy those from the same place......
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Thread Starter
Racer
Joined: Jan 2007
Posts: 253
Likes: 0
From: Winter Haven Florida
I'm guessing here:
machine work: 600
heads: 800
rotatingFORGED: 1500
1900 +/- couple hundred
I'm assembling it. The main reason I'm doing this. Quick question, though. Is it better to be internally balanced or externally. The engine stock now is external, but looking through parts to buy made me ask that question. If I went internally balanced, I'd need to replace my flywheel and harmonic balancer, right? Will do the flywheel regardless. Thanks,
Josh
machine work: 600
heads: 800
rotatingFORGED: 1500
1900 +/- couple hundred
I'm assembling it. The main reason I'm doing this. Quick question, though. Is it better to be internally balanced or externally. The engine stock now is external, but looking through parts to buy made me ask that question. If I went internally balanced, I'd need to replace my flywheel and harmonic balancer, right? Will do the flywheel regardless. Thanks,
Josh
Drifting
Joined: Apr 2002
Posts: 1,716
Likes: 4
From: New Baden Illinois
The difference between the 350, 383 & 396 is the stroke of the crank. The stock has 3.48, the 383 is 3.75, and the 396 is 3.875. The larger the stroke, the more torque.
I would just stay with the small block and build a nice 383 or 396 because your car is already set up for a small block. You won't have to convert all of brackets, springs, etc. like mentioned earlier.
If you want 350 rwhp, the Vortec heads are probably not the way to go. Generally, a nice set of Vortec heads will support about 400 hp at the crank. You are going to lose a lot of that before it gets to the wheels.
I also wouldn't go with a old camel hump heads. They are nice heads, but old technology. They won't get you to the numbers that you want to reach either. That being said, you don't have to go with aluminum heads. You can still reach your goals with iron heads.
I would just stay with the small block and build a nice 383 or 396 because your car is already set up for a small block. You won't have to convert all of brackets, springs, etc. like mentioned earlier.
If you want 350 rwhp, the Vortec heads are probably not the way to go. Generally, a nice set of Vortec heads will support about 400 hp at the crank. You are going to lose a lot of that before it gets to the wheels.
I also wouldn't go with a old camel hump heads. They are nice heads, but old technology. They won't get you to the numbers that you want to reach either. That being said, you don't have to go with aluminum heads. You can still reach your goals with iron heads.
Race Director
Joined: May 2005
Posts: 10,674
Likes: 122
From: Millington Illinois
St. Jude Donor '08-'09
http://forums.corvetteforum.com/show....php?t=1627978 These will support 500 FWHP and are new. Paid $1475 plus shipping
Instructor
Joined: Dec 2002
Posts: 222
Likes: 0
From: Leander TX
Doing a big block conversion isn't bad as long as you don't get a case of the "while I'm doing this I might as well.. " Accessory pulleys are the biggest pain doing the conversion to me, especially if you want to retain and A/C and pwr steering setup as I did. I went the expensive - but easy route (March serpentine)... sourcing a used 70s stock setup may be the least expensive way to go. The rest of the conversion is no big deal... including beefing up the suspension. But with SBs making 500+ hp with less weight.. and as said, parts are more plentiful.. its hard to justify going BB just considering $ per HP. Unless you want to go really big ci.. or just always wanted a BB like I did..