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Carb/exhaust question

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Old 05-08-2012, 12:28 AM
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JdCope
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Default Carb/exhaust question

I recently picked up 74 stingray with an original l48 (rebuilt a few years ago) and I am looking for some ways to increase power. I'm a novice but have some handy friends. One has recommended replacing the stock carbureter as an easy project to increase horse power. Any suggestions on one?
I'm also looking for a recommendation on exhaust system? Im in Cali but pre smog year. Went by a shop today and he said stick with 2 inch pipes and a new flow master would sound better but I won't see any increase in performance.
I appreciate any tips!
Old 05-08-2012, 12:32 AM
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briankeery
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How much $$$$$$$$ we talkin'?
Old 05-08-2012, 12:56 AM
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JdCope
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I'm pretty flexible, if it'll add power I'll spend the cash. I still have a lot to spend though including paint.
Old 05-08-2012, 08:13 AM
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7T1vette
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There is no "functional" reason to change carbs. You may need to rebuild yours, but that costs about $30 and 4 hours of your time (for the first one). The Q-Jet will equal [or better] any other carb on performance and it is the best of the bunch on efficiency (economy) under normal driving conditions.

To increase performance, tune the carb and distributor {re-curve it for performance}, which is essentially FREE hp; then change heads, cam, and exhaust on existing engine. Just make sure the heads and cam are compatible and will work together well.

Last edited by 7T1vette; 05-08-2012 at 08:16 AM.
Old 05-08-2012, 10:52 AM
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Roco71
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Originally Posted by 7T1vette
There is no "functional" reason to change carbs. You may need to rebuild yours, but that costs about $30 and 4 hours of your time (for the first one). The Q-Jet will equal [or better] any other carb on performance and it is the best of the bunch on efficiency (economy) under normal driving conditions.

To increase performance, tune the carb and distributor {re-curve it for performance}, which is essentially FREE hp; then change heads, cam, and exhaust on existing engine. Just make sure the heads and cam are compatible and will work together well.


Just about every performance modification has a trade off. Be aware of them before you start making them. Headers will increase horse power and require exhaust modifications . They may also require different brackets for mounting A/C and your alternator. Then there is the heat factor, they produce more heat.

One change leads to another.
Old 05-08-2012, 11:10 AM
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JdCope
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Thanks guys, I was reading about carb rebuilds last night and am going to give that a shot. As for the exhaust it sounds like I need to figure out what I'm going to do with the heads first. I think I can tackle replacing those but a friend warned me about screwing up my engine compression?
Old 05-08-2012, 11:14 AM
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Easy Mike
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Why not keep the car stock? After all, it has somehow managed to survive all these years with no major changes made to it. The stock 195hp L-48 will take you anywhere you want to go without problems.

Old 05-08-2012, 11:28 AM
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billla
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Have the Q-Jet rebuilt and tuned by a professional shop - there's nothing overly complex about doing it at home, but tasks that will need to be done such as rebushing the main throttle shaft are best left to the pros. At the very least, get the parts from one of these places and don't try to use the garbage "one size fits all" Q-jet rebuild kits.

http://www.cliffshighperformance.com/

http://www.smicarburetor.com/

From there, exhaust is your next step along with a mild cam upgrade and timing set replacement - both fairly inexpensive. Last step is a dyno tune...which will be the best $300 or so you ever spend. You'll end up with the best the engine can deliver - which is pretty good

Otherwise, you'll need to dig deeper into the engine which - as you note - is going to compete with other things that need attention. Figure on $1,500 or so for a mild head swap...if that's in the budget, then let's chat
Old 05-08-2012, 01:04 PM
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BKarol
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Before you start tearing down the carb, who told you that you have a carb problem? It could have been properly rebuilt last year. What is happening to make you think it needs a rebuild?

Also, you said the engine was rebuilt a few years ago. Have you been to a dyno or have any information about the rebuild. He might have done what people have said to do in this thread. You need more info from the PO.
Old 05-08-2012, 04:07 PM
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Roco71
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Originally Posted by Easy Mike
Why not keep the car stock? After all, it has somehow managed to survive all these years with no major changes made to it. The stock 195hp L-48 will take you anywhere you want to go without problems.

I am with Mike on this one. My 71 is a non-matching #'s has headers, aftermarket carburetor, intake, distributor, radiator only because it did not have any of those parts (I mean like nothing was there) when I got it. If your car is original and running it would keep it that way. Just my thoughts and I am an old hot rodder at heart.
Old 05-08-2012, 04:34 PM
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Rich's'78
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Default original l48 (rebuilt a few years ago)

Your first step should be to find out what was used in the rebuild, especially cam and pistons. To prove he spent the $ the PO should provide the build bill. That should list parts used. If he can't, find out where the rebuild was done and they may be able to tell you what they "normally" use. They may even have the build sheet on fille.
Old 05-08-2012, 07:28 PM
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FatRatShark
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Another option, pull the stock motor and store it, Drop in a crate motor with warranty.

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