Topic: 75 L48 engine
in Forum: C3 Engines
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Former Member
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Austin, TX - USA
Joined: 3/27/2006
Posts: 104
Vette(s): 73 coupe bought new in 1973 with only luggage rack, AM/FM radio, HD battery & Maplight as options. L48, 4 speed, Paint Med Met Blue 922 interior Dark saddle 418 special order. Repurchased 4/1/06 after 24 years.
Hi all, Its been a while since I posted. My 73 is still making strange tapping noise (not lifters, and not rod bearings) and I am still considering engine options. I need some advice. A friend of mine in our local Vette club built a hot big block for his 75 and he offered me his stock 75 L48 for $500. It has 101k miles on it and he says it doesn't use much oil or make unusual noises. If I got it and put a mild street cam in it would it make a decent replacement for my origional 73 L48 190hp 270ft-lb engine? What would I have to do to it to get something like 250hp? Would it be worth it, or should I just spring for a crate motor. I don't really want to spend 4k on a car I only drive maybe 50 miles a month.
Also his 75 vette is an automatic, do I have to change the flywheel to use it in my 73 M20 car?
John R
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Too me, this is another one of those personal preference decisions. If I was going to the trouble of puling an engine from my Vette I would do it right the first time. If the budget is the determining factor then the choices are limited. I don't think I would put a $500 tired engine in the car. If you need to do rings, bearings, machine work and heads plus a little sprucing up you will probably be $2000 deep. At that point a good crate engine is maybe an additional $1500. Too me, that would be money well spent.
In your case, with your unique ownership history with this car, you may want to consider rebuilding the original engine, sprucing it up along the way. I'm assuming that you are still running the original. If that is the case, I would definitely choose the latter. You have a great story to tell with your car. Again, it is your car and your decision. Think hard about it and have fun. I hope you keep this car forever.
Scott
ranger3 2007-09-21 18:38:07
In your case, with your unique ownership history with this car, you may want to consider rebuilding the original engine, sprucing it up along the way. I'm assuming that you are still running the original. If that is the case, I would definitely choose the latter. You have a great story to tell with your car. Again, it is your car and your decision. Think hard about it and have fun. I hope you keep this car forever.
Scott
Lifetime MemberModerator
Duncanville, TX - USA
Joined: 11/8/2003
Posts: 20214
Vette(s): #1-1974 L-48 4spd Cp Med Red Metallic/Black deluxe int w/AC/tilt/tele./p/w-p/b/
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#2-1985 Bright Red/Carmine Cp.L-98/auto
Member: NCRS, NCRS Texas, Corvette Legends of Texas
Why would you want to remove a(rated) 190hp engine and replace it with a 165hp engine? The '75 L48 was the lowest hp Corvette engine ever, next to the original "Blue Flame Special" of '53-'54...
You can swap the flywheels with no problem, but you would also need to add the pilot bushing in the crank to run the 4 spd.
If it were me(and it ain't), I would go ahead and get the '75 engine, have a little machine work done, buy some pistons that would squeeze a little more compression, and add a decent cam. With the right compression ratio, and a cam that matches the engine/trans/gear ratio, you could have a pretty decent set-up. 250hp? Maybe. With the stuff already mentioned, a good build on the quadrajet, some timing/ignition up-grades, maybe a set of headers, I don't see why not.
You can swap the flywheels with no problem, but you would also need to add the pilot bushing in the crank to run the 4 spd.
If it were me(and it ain't), I would go ahead and get the '75 engine, have a little machine work done, buy some pistons that would squeeze a little more compression, and add a decent cam. With the right compression ratio, and a cam that matches the engine/trans/gear ratio, you could have a pretty decent set-up. 250hp? Maybe. With the stuff already mentioned, a good build on the quadrajet, some timing/ignition up-grades, maybe a set of headers, I don't see why not.
Joel Adams
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Former Member
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Austin, TX - USA
Joined: 3/27/2006
Posts: 104
Vette(s): 73 coupe bought new in 1973 with only luggage rack, AM/FM radio, HD battery & Maplight as options. L48, 4 speed, Paint Med Met Blue 922 interior Dark saddle 418 special order. Repurchased 4/1/06 after 24 years.
I didn't realize the 75 was lower HP (165) than the 73. Hard to believe a 350 cu V8 can deliver only 165hp. GM must have worked hard to produce such an anemic engine! My 360cu 4 cylinder Lycoming with a single barrel carb designed in the 40's produces 180hp at 2700 RPM. If I have to do that much work to make it produce, I think I would rather either rebuild mine or go crate. Thanks for the info.
John R
I agree with Scott, for a few more $$, you can really raise the bar. IMO....
Lifetime MemberSHELBYVILLE, TN - USA
Joined: 7/5/2002
Posts: 3942
Vette(s): 1976 L48 auto
1978 L82 4speed
1994 LT1 6speed
1978 L82 4speed
1994 LT1 6speed
there are other crate engines available than the before mentioned zz4 in another thread. i just glanced at Jeg's website, and they have 2 260 hp chevy 350 GM crate engines, one for about 1500, the other for about 1800... one is a little different from the other(different cam profile,pistions, etc...). Crates are an easier way to go, though rebuilding your own gives it a more "personal" touch. As Ranger said, rebuilding an engine can get up to 2000, depending on what has to be done to the engine(machine work, etc)... just another option ...
links to the two engines at Jegs... i'm sure there are other places that similar engines can be found...
StingrayJim 
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Why take another motor instaed of fixing the one you have? seems like $500 for a motor just to fix a little noise is a bit much. And then you will want to spend more $ on additional parts too. If your motor isn't worth fixing then buy a crate motor. You get what you pay for.
Redwingvette 2007-09-22 04:45:00
JMO
Brian - NCM Lifetime Member
73 coupe L48, Flat-top pistons, Performer RPM Heads, Crane Cam and roller rockers, Holley 650 vac sec. Performer intake,
3.55 gear BTO 200-4R trans,
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Lifetime MemberGreensburg, IN - USA
Joined: 9/24/2003
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Vette(s): Previous: 1984 Coupe, 1988 Maroon Coupe, 1989 Coupe, 2001 Roadster Present: 1967 Stingray Roadster, 1976 Stingray Coupe, 1989 Roadster..
Although I like the advantages of the crate motor I tend to agree that with your history with this car I would rebuild. I would make it a wolf in sheeps clothing. (hot but semi stock look)
"If it were me(and it ain't), I would go ahead and get the '75 engine, have a little machine work done, buy some pistons that would squeeze a little more compression, and add a decent cam. With the right compression ratio, and a cam that matches the engine/trans/gear ratio, you could have a pretty decent set-up. 250hp? Maybe. With the stuff already mentioned, a good build on the quadrajet, some timing/ignition up-grades, maybe a set of headers, I don't see why not."
I like Joels suggestion except I would raise the bar on the OEM engine. Providing you can afford the downtime from the car. (2 months?)
You can walk away with something pretty nice that is more aggressive. On the other hand you can always buy the crate engine an restore the OEM ata a later date if you don't mind having it sit around.Tuxblacray 2007-09-23 16:22:12
"If it were me(and it ain't), I would go ahead and get the '75 engine, have a little machine work done, buy some pistons that would squeeze a little more compression, and add a decent cam. With the right compression ratio, and a cam that matches the engine/trans/gear ratio, you could have a pretty decent set-up. 250hp? Maybe. With the stuff already mentioned, a good build on the quadrajet, some timing/ignition up-grades, maybe a set of headers, I don't see why not."
I like Joels suggestion except I would raise the bar on the OEM engine. Providing you can afford the downtime from the car. (2 months?)
You can walk away with something pretty nice that is more aggressive. On the other hand you can always buy the crate engine an restore the OEM ata a later date if you don't mind having it sit around.
Former Member
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Yelm, WA - USA
Joined: 7/12/2007
Posts: 356
Vette(s): 1979 L82 4 speed Scat 383 crank 190 cc Procomp Aluminum Heads 202 160 stainless valves GM Powder metal rods Speedpro H860CP Hypereutectic pistons 280 cam hydralic HEI Pro comp 1.6 roller rockers Mighty Demon 750 Sanderson CC1AP Hedders.
I'm new to vette's but I've run into two kinds of people since I started building my 79. The kind that act disgusted and get all snooty when they find out youre not keeping it exactly original and the wonderfull people on this site who really seem to enjoy their cars. I got a set of motofeet tucked my L-82 in a corner and got a 383 so I could have a little fun. I like Jeg's but I also like doing business locally so I called around and found a race shop that had what I was looking for. 
That's pretty cool you still have that car!
Lifetime MemberGreensburg, IN - USA
Joined: 9/24/2003
Posts: 5189
Vette(s): Previous: 1984 Coupe, 1988 Maroon Coupe, 1989 Coupe, 2001 Roadster Present: 1967 Stingray Roadster, 1976 Stingray Coupe, 1989 Roadster..
[QUOTE=79rebuild]
Takes all kinds to make a community. There are purist who enjoy a car untouched, those that like slight modification (enthusiast) and those that like um modified (Rodders).
To me what is a defining point is do they have the PASSION. Myself I have a pasionate affair with the car to the point that I can appreciate all of th types of people mentioned above if their roots are drivin towards the the preservation of the car and its name.
It's that enjoyment that we share that brings us together as a forum, club, group, friends, and will continue to promote Vettes into the future.
Oh yeah and like the bumpersticker says"Mean People Suck!"
Tux...Tuxblacray 2007-09-23 16:24:42
I'm new to vette's but I've run into two kinds of people since I started building my 79. The kind that act disgusted and get all snooty when they find out youre not keeping it exactly original and the wonderfull people on this site who really seem to enjoy their cars. I got a set of motofeet tucked my L-82 in a corner and got a 383 so I could have a little fun. I like Jeg's but I also like doing business locally so I called around and found a race shop that had what I was looking for. That's pretty cool you still have that car!
Takes all kinds to make a community. There are purist who enjoy a car untouched, those that like slight modification (enthusiast) and those that like um modified (Rodders).
To me what is a defining point is do they have the PASSION. Myself I have a pasionate affair with the car to the point that I can appreciate all of th types of people mentioned above if their roots are drivin towards the the preservation of the car and its name.
It's that enjoyment that we share that brings us together as a forum, club, group, friends, and will continue to promote Vettes into the future.
Oh yeah and like the bumpersticker says"Mean People Suck!"
Tux...
in Forum: C3 Engines
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