Boosting power in a 77 vette
Thread Starter
6th Gear
Joined: May 2011
Posts: 6
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From: Agawam MA
Boosting power in a 77 vette
I bought a '77 vette in summer of 2010 - ha, this was before I knew anything about corvettes! It took a lot to get it inspected. Last summer I had the interior redone - now I want more power. Someone told me "heads & cams" but I'm not a mechanic. What about tuning, timing and a nice dual exhaust? Anyone out there done this?
Bob
Bob
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
The least expensive way to get decent power from the L-48 engine is to recurve the distributor for best 'performance', rebuild and tune the carb, tune-up the ignition system with new components, and put a set of true dual exhausts on it. If you do anything more, you will essentially have to do a major rebuild of the engine. {New heads require a better cam and a better intake manifold, which requires better headers, etc, etc.} If you go down that road...go all the way.....or not at all.
Burning Brakes
Joined: Apr 2007
Posts: 1,039
Likes: 62
From: Kona Hawaii
Have a 76 with a warmed over L48.Dual exhaust,crower 00320 solid cam cool face lifters,roller rockers,aluminum heads,air gap manifold 570 holley carb.Combo is very streetable and its quick.A Richmond 6 spd trans backs up the motor.Been doing the mods over several years as funds allow...Good luck![IMG]
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Safety Car
Joined: Jan 2009
Posts: 3,736
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From: anchorage ak
I would say Long tub headers a must, cam heads & intake make the bigest difference, with the quote you get what you pay for being the truest in hot roding a sbc, dont be skimpy when it comes to the heads, roller cam is always the way to go. Research on the web is the way to go, dart & afr have a wealth of knowladge, the best part about building an engine is researching the build, building it, and seeing how your research paid off. The knowledge you build upon the way is priceless.
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
The least expensive way to get decent power from the L-48 engine is to recurve the distributor for best 'performance', rebuild and tune the carb, tune-up the ignition system with new components, and put a set of true dual exhausts on it. If you do anything more, you will essentially have to do a major rebuild of the engine. {New heads require a better cam and a better intake manifold, which requires better headers, etc, etc.} If you go down that road...go all the way.....or not at all.
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Have a 76 with a warmed over L48.Dual exhaust,crower 00320 solid cam cool face lifters,roller rockers,aluminum heads,air gap manifold 570 holley carb.Combo is very streetable and its quick.A Richmond 6 spd trans backs up the motor.Been doing the mods over several years as funds allow...Good luck![IMG][/IMG]
[/IMG]Scott
Le Mans Master
Joined: Jun 2004
Posts: 6,231
Likes: 65
From: Seattle WA
St. Jude Donor '14
Agree with all the above - start with a solid, complete tune. More folks "rediscover" the power in their 'Vette with this process than any other single investment. I'd agree with exhaust next...and the final choice is a "top" - heads/cam/intake. Note that for a top to be effective, an evaluation of the condition of the shortblock is required. Compression and leak-down test as a minimum and also a hard look at the odometer.
Conversations about "tops" have two aspects - originality and budget. Deciding on both of these helps get some specific guidance...otherwise the options are unlimited
Conversations about "tops" have two aspects - originality and budget. Deciding on both of these helps get some specific guidance...otherwise the options are unlimited
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Verdad Gallardo
Cruising
Joined: Jul 2009
Posts: 14
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From: Lockport IL.
Upgrades to L48
I tried everything I could think of & some. At the end of the day, it's still a L48. By the time you rebuild it, to hopefully get what you think you want, it was easier, at least for me, to just put a grate motor in it, done. I got exactly what I wanted & more. I got the motor from Jeg's, pan to air cleaner, for a little over 4K. Upgrades & / or rebuild were close to that. I got 420HP, warranty, & a big smile out of it. BUT & there is always a but, it's a snowballing effect. It's a 77. When I was in there, with motor out of way, & figured I might as well start replacing what looked bad. That ended up being ball joints, bushings, springs, shocks,etc......... Rebuilt the trans, radiator, fixed the core support, & sandblasted / painted everything I could get at. Was it worth it? YES! The parts I replaced were only a few hundred dollars & some time. It took time, all winter, but it is just a real fun car to drive now.The only thing I have to do is change out the rear end. She's got a top end that won't quit but with this kind of power, I think I want stop sign to stop sign.
Just my opinion, good luck!
Just my opinion, good luck!
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
I have a 1980 L48, it had an Edelbrock Performer on it when I bought it. I installed an exhaust system from Corvette Central (block hugger headers, 2 1/2" dual exhaust, Magna flow mufflers) re-curved the distributor, and tuned the carb. It made a noticable difference in power and throttle response. Setting up the spark timing properly made the biggest difference, surprisingly, and was by far the cheapest mod. Like, less than 40 bucks. Check out this thread on timing, bro:
http://forums.corvetteforum.com/c3-t...long-post.html
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Advanced
Joined: Jan 2012
Posts: 83
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From: Chicxulub Yucatán
I bought a '77 vette in summer of 2010 - ha, this was before I knew anything about corvettes! It took a lot to get it inspected. Last summer I had the interior redone - now I want more power. Someone told me "heads & cams" but I'm not a mechanic. What about tuning, timing and a nice dual exhaust? Anyone out there done this?
Bob
Bob
I'm not sure what you have for a budget, but something that I'd recommend is an entirely different approach. 700R4...it will make your current combination feel a lot stronger and improve your MPG.
http://www.700r4.com/faq/ratiocmp.shtml
MxB
Drifting
Joined: Dec 2004
Posts: 1,714
Likes: 42
From: Austin Texas
I think Mexican Bob has a very good point.
If your car has a TH350 auto and 3.08 rear gears, adding horse power alone can leave you wanting more... My car has a rebuilt l48 with a th400. With headers and Performer intake, It rear wheel dyno'd at 187 hp. I added heads and cam and got the rear wheel power up to 270 hp. This is a nice motor for me for what I have invested.
However, with 3.08 gears, it was still a dog from a stop. A 2800 torque converter and 3.55 rear gears transformed the car although I had to give up some top end speed and gas mileage.
A 700r4 would be a great first mod. Plenty of torque off the line and overdrive. I myself will be converting to a 2004R in the future.
If your car has a TH350 auto and 3.08 rear gears, adding horse power alone can leave you wanting more... My car has a rebuilt l48 with a th400. With headers and Performer intake, It rear wheel dyno'd at 187 hp. I added heads and cam and got the rear wheel power up to 270 hp. This is a nice motor for me for what I have invested.
However, with 3.08 gears, it was still a dog from a stop. A 2800 torque converter and 3.55 rear gears transformed the car although I had to give up some top end speed and gas mileage.
A 700r4 would be a great first mod. Plenty of torque off the line and overdrive. I myself will be converting to a 2004R in the future.
Melting Slicks
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From: SUFFIELD CT USA 2023 C8 CORVETTE UN-MODIFIED FINALIST
2023 C8 of the Year Finalist - Unmodified
Race Director
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From: Smalltownville Michigan
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St. Jude Donor '09
Instructor
Joined: Mar 2012
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From: Sayreville NJ
The least expensive way to get decent power from the L-48 engine is to recurve the distributor for best 'performance', rebuild and tune the carb, tune-up the ignition system with new components, and put a set of true dual exhausts on it. If you do anything more, you will essentially have to do a major rebuild of the engine. {New heads require a better cam and a better intake manifold, which requires better headers, etc, etc.} If you go down that road...go all the way.....or not at all.
I already have the true dual exhaust and I'm looking to further improve hp on the super cheap and without rebuilding my engine