L48 upgrade why not???
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 28
Likes: 0
From: castaic ca
L48 upgrade why not???
Most of us are always asking how do i get more hp. I'm not a mechanic but I know the basics.
When I looked into replacing the camshaft, heads and intake it was going to run at least $2k paying someone to do it.
Tell me why shouldn't buy this 260hp from jegs for 1,500 (free shipping too) change out the cam put factory intake on it and call it good with maybe 275- 280 hp and have a brand new engine from top to bottom?
Is this a decent idea or am I way off base here.
specs for engine
Chevrolet Performance 10067353 GM Goodwrench 350ci Engine
GM Goodwrench 350ci Engine
260HP/350TQ
4-Bolt Main
3-Year/100,000 Mile Warranty
never mind now that i check the website is saying it's not compatible with a 73 vette
When I looked into replacing the camshaft, heads and intake it was going to run at least $2k paying someone to do it.
Tell me why shouldn't buy this 260hp from jegs for 1,500 (free shipping too) change out the cam put factory intake on it and call it good with maybe 275- 280 hp and have a brand new engine from top to bottom?
Is this a decent idea or am I way off base here.
specs for engine
Chevrolet Performance 10067353 GM Goodwrench 350ci Engine
GM Goodwrench 350ci Engine
260HP/350TQ
4-Bolt Main
3-Year/100,000 Mile Warranty
never mind now that i check the website is saying it's not compatible with a 73 vette
Last edited by thom powers; Mar 2, 2014 at 11:32 PM.
Burning Brakes
Joined: Feb 2006
Posts: 1,223
Likes: 4
From: Regina Saskatchewan
I've gone through this whole thing. Upgraded the L48 with heads, intake, exhaust, tranny, then pulled the L48 and stuck in a 383. Best bang for the buck was a 700R tranny. If I could only afford one thing - thats what it would be. Its like putting 4.60 gears AND 2.48s into your rear end.
Burning Brakes
Joined: Sep 2012
Posts: 818
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From: coon rapids mn
find a good hot rod shop ,and talk to them about engine R&R .consider using your current short block for a 383 stroker .find a good local engine builder ,and talk to him about a mild 383 sbc build .you can make 400 + hp with iron heads and a mild cam .use a performer intake to fit under the hood and retain the Q-jet .
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 28
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From: castaic ca
Pro
Joined: Nov 2013
Posts: 730
Likes: 37
From: Catoosa Okla
100,000 mile LQ4. Put some LS2 heads on it. Replace the camshaft. You now have over 450 hp at your disposal. Back it with a Tremec 6 speed or a 4L60e. They both have overdrives. Toss a set of 3:70's in the rear. Hang on tight. Enjoy 24 mpg. Need I say more???
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
Here's something to think about regarding the Goodwrench engine: If you bought the engine, and a 3.75" stroke crank, (which can be had pretty cheaply) and milled .110" off the top of each piston, you'd have flat-top pistons, sitting at zero deck height, which would have a reasonable compression ratio and good quench with a .041" head gasket and the 76cc heads. it would not be .030" over, so it would only displace 377 ci, but still, a pretty cheap stroker motor could be had. 1500 bucks for the engine itself, and however much the milling and balancing would cost. Discuss.
Scott
Scott
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Race Director
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
Here's something to think about regarding the Goodwrench engine: If you bought the engine, and a 3.75" stroke crank, (which can be had pretty cheaply) and milled .110" off the top of each piston, you'd have flat-top pistons, sitting at zero deck height, which would have a reasonable compression ratio and good quench with a .041" head gasket and the 76cc heads. it would not be .030" over, so it would only displace 377 ci, but still, a pretty cheap stroker motor could be had. 1500 bucks for the engine itself, and however much the milling and balancing would cost. Discuss.
Scott
Scott
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
It's been about 25 years since I had any machine work done, but would milling 8 pistons and balancing a rotating assembly really cost 1500 bucks? Wow! No wonder crate engines are so popular! if you have a friend (or even a friend of a friend) who has a milling machine, you could probably have the pistons milled pretty cheaply, (might even be able to do it on a lathe) and I can't see how balancing a rotating assembly could cost more than 2-300 bucks. If I'm that far out of touch, could somebody please straighten me out?
I did some number crunching with my compression ratio calculator, and the above combination, with a .041", 4.1" wide head gasket, figuring zero volume for the piston (even though some of the eyebrows would still be there, so it would have maybe a couple of cc) and I got 10.1:1 for a static compression ratio. Using a Summit Racing 1103 camshaft, I get a 7.65 dynamic compression ratio.
Someone on this forum mentioned this idea a while ago, and I've been thinking about it ever since. I can't remember who it was, but he said he knew someone who had built several of these engines, and they ran fine.
Scott
I did some number crunching with my compression ratio calculator, and the above combination, with a .041", 4.1" wide head gasket, figuring zero volume for the piston (even though some of the eyebrows would still be there, so it would have maybe a couple of cc) and I got 10.1:1 for a static compression ratio. Using a Summit Racing 1103 camshaft, I get a 7.65 dynamic compression ratio.
Someone on this forum mentioned this idea a while ago, and I've been thinking about it ever since. I can't remember who it was, but he said he knew someone who had built several of these engines, and they ran fine.
Scott
Race Director
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
It's been about 25 years since I had any machine work done, but would milling 8 pistons and balancing a rotating assembly really cost 1500 bucks? Wow! No wonder crate engines are so popular! if you have a friend (or even a friend of a friend) who has a milling machine, you could probably have the pistons milled pretty cheaply, (might even be able to do it on a lathe) and I can't see how balancing a rotating assembly could cost more than 2-300 bucks. If I'm that far out of touch, could somebody please straighten me out?
I did some number crunching with my compression ratio calculator, and the above combination, with a .041", 4.1" wide head gasket, figuring zero volume for the piston (even though some of the eyebrows would still be there, so it would have maybe a couple of cc) and I got 10.1:1 for a static compression ratio. Using a Summit Racing 1103 camshaft, I get a 7.65 dynamic compression ratio.
Someone on this forum mentioned this idea a while ago, and I've been thinking about it ever since. I can't remember who it was, but he said he knew someone who had built several of these engines, and they ran fine.
Scott
I did some number crunching with my compression ratio calculator, and the above combination, with a .041", 4.1" wide head gasket, figuring zero volume for the piston (even though some of the eyebrows would still be there, so it would have maybe a couple of cc) and I got 10.1:1 for a static compression ratio. Using a Summit Racing 1103 camshaft, I get a 7.65 dynamic compression ratio.
Someone on this forum mentioned this idea a while ago, and I've been thinking about it ever since. I can't remember who it was, but he said he knew someone who had built several of these engines, and they ran fine.
Scott
And it would most likely void any warranty.....
Le Mans Master
Joined: Mar 2008
Posts: 5,948
Likes: 72
From: Oxford MA-----You just lost the game!!!!
http://www.summitracing.com/parts/es...make/chevrolet
http://www.summitracing.com/parts/fe...make/chevrolet
http://www.summitracing.com/parts/su...make/chevrolet
276 bucks for the crank, 47 bucks for the gasket set, 60 bucks for the cam.
1500 for crate engine
276 for crank
47 for gasket set
Let's say 300 for balancing
Let's say 200 for milling
60 for the cam
2383, call it 2500 bucks with shipping and incidentals. And I could be way off on the machining costs. You could probably buy pistons for less than the cost of machining them. You'd still have to have it balanced, though. And, um...yeah, it would definitely void the warranty! If you were a machinist it might still be a good deal!
Well, we're just bouncing stuff off the wall here, right? No harm done. Good luck on however you end up going!
Scott
http://www.summitracing.com/parts/fe...make/chevrolet
http://www.summitracing.com/parts/su...make/chevrolet
276 bucks for the crank, 47 bucks for the gasket set, 60 bucks for the cam.
1500 for crate engine
276 for crank
47 for gasket set
Let's say 300 for balancing
Let's say 200 for milling
60 for the cam
2383, call it 2500 bucks with shipping and incidentals. And I could be way off on the machining costs. You could probably buy pistons for less than the cost of machining them. You'd still have to have it balanced, though. And, um...yeah, it would definitely void the warranty! If you were a machinist it might still be a good deal!
Well, we're just bouncing stuff off the wall here, right? No harm done. Good luck on however you end up going!
Scott
Race Director
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
http://www.summitracing.com/parts/es...make/chevrolet
http://www.summitracing.com/parts/fe...make/chevrolet
http://www.summitracing.com/parts/su...make/chevrolet
276 bucks for the crank, 47 bucks for the gasket set, 60 bucks for the cam.
1500 for crate engine
276 for crank
47 for gasket set
Let's say 300 for balancing
Let's say 200 for milling
60 for the cam
2383, call it 2500 bucks with shipping and incidentals. And I could be way off on the machining costs. You could probably buy pistons for less than the cost of machining them. You'd still have to have it balanced, though. And, um...yeah, it would definitely void the warranty! If you were a machinist it might still be a good deal!
Well, we're just bouncing stuff off the wall here, right? No harm done. Good luck on however you end up going!
Scott
http://www.summitracing.com/parts/fe...make/chevrolet
http://www.summitracing.com/parts/su...make/chevrolet
276 bucks for the crank, 47 bucks for the gasket set, 60 bucks for the cam.
1500 for crate engine
276 for crank
47 for gasket set
Let's say 300 for balancing
Let's say 200 for milling
60 for the cam
2383, call it 2500 bucks with shipping and incidentals. And I could be way off on the machining costs. You could probably buy pistons for less than the cost of machining them. You'd still have to have it balanced, though. And, um...yeah, it would definitely void the warranty! If you were a machinist it might still be a good deal!
Well, we're just bouncing stuff off the wall here, right? No harm done. Good luck on however you end up going!
Scott
I was just thinking of the op's budget....
I considered the same engine myself when I was kicking around ideas...
Thread Starter
Intermediate
Joined: Oct 2013
Posts: 28
Likes: 0
From: castaic ca
Race Director
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
http://www.blueprintengines.com/inde...1-engine-specs
Here's the link to my swap
http://forums.corvetteforum.com/c3-t...int-383-a.html
So far so goo and this engine is VERY strong...
No tearing apart and voiding the warranty, no machining, no re-assembly...just pull old and replace
If not that engine, something similar. I just think it's a great price.
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,118
From: Crossville TN
If your L-48 is in reasonably good shape, that 'new' crate motor will provide about the same power you already have. The 260HP rating is from an engine dyno, without accessories. That same L-48 in 1971 (engine dyno, without accessories SAE rating system) produced 270 HP.
Significant money for NO GAIN.
There is nothing wrong with your concept. But, you should buy a crate engine that will provide MORE POWER, if that's what you are looking for. You need an engine rated at more than 300 hp, if you really want to feel a difference.
Or, you can put the same money (or less) into aluminum heads, new roller cam & lifters, and headers w/dual exhaust on your present engine.
Significant money for NO GAIN.
There is nothing wrong with your concept. But, you should buy a crate engine that will provide MORE POWER, if that's what you are looking for. You need an engine rated at more than 300 hp, if you really want to feel a difference.
Or, you can put the same money (or less) into aluminum heads, new roller cam & lifters, and headers w/dual exhaust on your present engine.
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
I was 224hp/289tq at rear wheels in 2003 with the basics (Lars qjet, Edebrock intake, Accel w/ perf advance, headers/duals, Northern Auto Parts Street Performance kit w/ pistons, stamped steel rockers, cam/lifters, timing set, seals, etc and DART Iron Eagles). Then, 700R4 and 3.54's and it really got fun.
Now, I just finished (2013) another top-end refresh and added retro roller cam from Comp (spent total about $2,500 on parts I installed and those I bought for install @ retirement. About $2,500 spent on parts AND tools.
Perhaps I should have just stepped up to the equivalent of the Blueprint 430hp/450tq back in 1999 and been $$$ ahead.
However, it was fun to increase performance incrementally over 17 years. Of course, I don't have 430hp/450tq but it is definitely around 350hp, 400tq. VERY spirited performance, I learned a lot (doing most of the work save for machining) and got to know some great folks on the forum.
Last edited by TedH; Mar 3, 2014 at 03:07 PM.
Race Director
Joined: Feb 2006
Posts: 12,239
Likes: 19
From: Chino CA
TedH - I did miss out on the fun of building it myself...I was really looking forward to that believe it or not!
I went so far as to pick up a Gen1 4-bolt from CL (never bored - I measured)...but when I started adding up the numbers...parts, machining, etc - it just wasn't worth it
Someday I still want to build one myself though!
(Anybody in So-Cal want a free 4-bolt block...come and get it in Chino!)
I went so far as to pick up a Gen1 4-bolt from CL (never bored - I measured)...but when I started adding up the numbers...parts, machining, etc - it just wasn't worth it
Someday I still want to build one myself though!
(Anybody in So-Cal want a free 4-bolt block...come and get it in Chino!)
Le Mans Master
Joined: Feb 1999
Posts: 8,351
Likes: 75
From: Tampa Bay FL
TedH - I did miss out on the fun of building it myself...I was really looking forward to that believe it or not!
I went so far as to pick up a Gen1 4-bolt from CL (never bored - I measured)...but when I started adding up the numbers...parts, machining, etc - it just wasn't worth it
Someday I still want to build one myself though!
(Anybody in So-Cal want a free 4-bolt block...come and get it in Chino!)
I went so far as to pick up a Gen1 4-bolt from CL (never bored - I measured)...but when I started adding up the numbers...parts, machining, etc - it just wasn't worth it
Someday I still want to build one myself though!
(Anybody in So-Cal want a free 4-bolt block...come and get it in Chino!)
MrJlr, I am envious
