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Discussion Starter #1
I just got my 350 260HP crate engine installed with edelbrock intake manifold & flowmasters(installed by P.O.) and would like to know how much more horse power I would gain if I installed a performance carburetor, headers & cam. And would it be a noticeable difference in HP?

I want more power, but don't want to go too crazy with engine modifications or replacing heads or what not.

Thanks.
 

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Discussion Starter #2
My mechanic recommended a Holley carburetor and said it would definitely boost my HP gain. Any thoughts?
 

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My mechanic recommended a Holley carburetor and said it would definitely boost my HP gain. Any thoughts?
Really depends on what carb you have on there now. I like Holleys, but that makes me bias against other manufactures.
 

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Discussion Starter #5
You could probably muster another 30-40hp out of it with a cam, carb and headers. The difference between 260hp and 300hp will be very noticeable.
That's exactly what I needed to know. I guess I can stay away from headers since many people are having issues with performance headers. Another silly question. How much will it affect mpg?

Really depends on what carb you have on there now. I like Holleys, but that makes me bias against other manufactures.
Currently stock. I was thinking Edelbrock, but any decent performance carb will work.
 

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Holleys are great performers but tend to be thirsty. They really are racing carbs in street clothing. The addition of moderate cam will help. But a word if caution ..don't go too radical with the duration. Your motor doesn't have enough compression to benefit from a stout cam grind. Your torque converter won't be happy either if you need to idle too high. The loss of manifold vacuum needs to be
considered.

I suggest you visit Comp Cams interactive website. It will lay out the differences between their cams and what other components work well with each. Great site..check it out.

You should have no problem finding a moderate cam, carb and pipes combo to make you smile.
Do not make the common mistake of putting a huge carb on it. Sounds good but slows you down. According to the gurus @Quick Fuel claim that a 650cfm carb is the oerfect size for a 350cid motor revving to about 6500!.

Good luck.

Don't forget the MSD ignition. Best thing you can do for your motor.:nanawrench:
 

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Discussion Starter #8
Holleys are great performers but tend to be thirsty. They really are racing carbs in street clothing. The addition of moderate cam will help. But a word if caution ..don't go to radical with the duration. Your motor doesn't have enough compression to benefit from a stout cam grind. Your torque converter won't be happy either if you need to idle too high. The loss of manifold vacuum needs to be
considered.

I suggest you visit Comp Cams interactive website. It will lay out the differences between their cams and what other components work well with each. Great site..check it out.

You should have no problem finding a moderate cam, carb and pipes combo to make you smile.
Do not make the common mistake of putting a huge carb on it. Sounds good but slows you down. According to the gurus @Quick Fuel claim that a 650cfm carb is the oerfect size for a 350cid motor revving to about 6500!.

Good luck.

Don't forget the MSD ignition. Best thing you can do for your motor.:nanawrench:
Great info I will check them out.

HQDeezy, If you're even mentioning gas mileage with that engine you're going the WRONG way !
Why? I was just curious to know how it would affect mpg (if I were to ever make it my DD )although mpg isn't a big importance to me since it's just a weekend cruiser. I'm just wanted to do my due diligence.
 

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Gas mileage and Performance don't really mix well. With your combo, ok/good fuel economy will strictly be controlled by your right foot.

I would stay away from Edlebrock carbs (Just my opinion). I have never had very good luck with them. I like Holleys.
 

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Mountain Man has a store on Ebay. Here is his email address: [email protected]

I don't think headers should necessarily be out of your equation. People have problems because they buy cheap headers or buy the wrong fitment. Headers flow like crazy and give you some obviously better sound, if that's what you want.

For fuel mileage, if a Quadrajet gives you, for example, 15 mpg, a 600-670cfm Holley with vacuum secondaries (a must for the street cars) will probably deliver 12-13 mpg. Quadrajets are more efficient, and Mountain Man can build them for performance or stock rebuild. Holleys are pretty easy to work on/upgrade, and parts are cheap as dirt. As 1320ElkySS said, your fuel mileage with your new, more powerful, louder engine will be controlled by your impulsive right foot.
 

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Every time I see people having difficulty with headers it's always with "other brands". There's a bunch of threads on what headers will fit and what modifications will need to be done if any to get them to fit. I know there's a set that Hooker makes that are priced well. JMO that if you're going to put in a more performance driven cam and carb, the headers are just one of those upgrades that go along with them. You know, get the air in, and get it out :poke:
 

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HQD, I see you are in the Bay Area, so I assume you are under pretty strict SMOG rules. A mild cam can be installed without blowing your emissions, but I believe you will have to stay with the CCC carb and distributor, along with the ECM. Only CARB approved headers are Edelbrock TES and Hooker (???Number). Both are out of production, as far as I know.
 

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how much more horse power I would gain if I installed a performance carburetor, headers & cam. And would it be a noticeable difference in HP?
That 260 horsepower is rated with headers, and a 4bbl from the factory (last time I checked). So with manifolds on you are already under that. Heck, that is probably a "gross" rating with nothing more than the water pump on it.

A mild cam will be good since the compression is so low in those engines. I think I've seen it actually spec'd out under 8:1 when someone measured it. Was something like 7.8:1...

For the record I had one of those engines with the old "350" hp cam (I forget the grind but it was around 224/.450). Combined that with 3.08's and a stock converter and the car was a real dog. I swapped to a summit racing copy of the old edelbrock performer which is a bit smaller and the car felt a lot better.
 

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Jim, you are right about the 260 hp claim- it was with headers and no accessories. That being said, the only difference between the 260 hp version and the 290 hp version was the cam- every other part on the parts list was identical!

HQD, is the engine still under warranty? If so, changing anything internally will void it. Might consider a change in rear gearing, if you haven't done that yet. With the TH350 trans, 3.42 is about as strong as I would go, but it will feel like you've added 100 hp.
 

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With the TH350 trans, 3.42 is about as strong as I would go, but it will feel like you've added 100 hp.

EXACTLY what I was thinking about for my own elky..and I didn't even have to make my own thread..thanks lol :)
 

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Discussion Starter #19
Jim, you are right about the 260 hp claim- it was with headers and no accessories. That being said, the only difference between the 260 hp version and the 290 hp version was the cam- every other part on the parts list was identical!

HQD, is the engine still under warranty? If so, changing anything internally will void it. Might consider a change in rear gearing, if you haven't done that yet. With the TH350 trans, 3.42 is about as strong as I would go, but it will feel like you've added 100 hp.
You're right about the warranty, I forgot about that so changing an internals is out of the question until the warranty has bee voided. I'll probably look for a simple bolt header for the time being and work on suspension. And surprisingly the car has a good amount of torque when I floored the pedal so I'll also look at changing the gears.

And to everyone who shared their expertise I do greatly appreciate it.
 
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