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Old 11-10-2017, 11:40 AM
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Trying to get 300 or more HP out of 71' 350

Just got an '86 Camaro with a 350 swap, and didn't find out much about the engine before I received it. Was able to determine that the engine is a '71 350 out of an El Camino of that year. It has a 600cfm 1405 Edelbrock 4-barrel carb and Weiand X-Celerator intake manifold on it, that I can see. Not sure how much HP it's making at the moment, but trying to get 300 or more if I'm not already there. New to modding, as this is my first muscle car, so any advice on some things I could do to get better performance and hp potential out of this engine would be great. Stock exhaust on it, cut off at the muffler, so I plan on replacing that at some point. Everything else really, is stock as far as I can see, besides cosmetics. Thanks in advance

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Old 11-12-2017, 10:46 AM
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Your goal of 300 hp will not be a problem. Do you know the model of the heads that are on the car or see any identifiers? If you do, then you can get a pretty good idea of the capable hp already in the motor.
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Old 11-12-2017, 12:07 PM
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Not sure on what heads are in it. I'd assume stock that came with engine, but I'll have to pull valve covers and find the casting numbers
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Old 11-12-2017, 12:42 PM
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What's the casting code and suffix code on the motor?
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Old 11-12-2017, 12:50 PM
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A decent (budget) set of heads, headers, and proper tune and you'll be at 325-350. For that matter, a decent valve job on your heads with 9.5-10:1 compression with an XE262 or XE268 cam and you'll be at your goal.

If the base motor is in good shape - compression/leak down wise - then you can probably get there with a cam and headers.
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Old 11-12-2017, 12:57 PM
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Quote:
Originally Posted by RWENUTS View Post
What's the casting code and suffix code on the motor?
Casting code is 3970010
Suffix is CGC. That pointed me to 71 El Camino 350 engine
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Old 11-12-2017, 01:01 PM
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Quote:
Originally Posted by 64nailhead View Post
A decent (budget) set of heads, headers, and proper tune and you'll be at 325-350. For that matter, a decent valve job on your heads with 9.5-10:1 compression with an XE262 or XE268 cam and you'll be at your goal.

If the base motor is in good shape - compression/leak down wise - then you can probably get there with a cam and headers.
I was planning on doing some compression testing soon here actually. Engine, so far, runs great, sounds great, no knocking, and looks pretty clean. Any recommended heads to look into?
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Old 11-12-2017, 01:05 PM
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Being a 1971 you need to get the VIN id off the right front pad, the block casting number off the left side bell housing boss below the head deck, and the head casting numbers between one of the valve pairs of the head casting by removing a rocker cover to expose this area.

The 71, 350's were rated 165 to 300 hp depending on the combination of head, intake and carburation, and cam.

Since this has been touched at least on the intake side, who knows what's really inside, but the VIN id and casting numbers are the place to start.

Bogie
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Old 11-12-2017, 01:49 PM
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Quote:
Originally Posted by BogiesAnnex1 View Post
Being a 1971 you need to get the VIN id off the right front pad, the block casting number off the left side bell housing boss below the head deck, and the head casting numbers between one of the valve pairs of the head casting by removing a rocker cover to expose this area.

The 71, 350's were rated 165 to 300 hp depending on the combination of head, intake and carburation, and cam.

Since this has been touched at least on the intake side, who knows what's really inside, but the VIN id and casting numbers are the place to start.

Bogie
Ill get the casting numbers for the heads when I can, but I may need to order new gaskets to be on the safe side when I take the valve covers off. They're replacement valve covers for sure, but I'd rather err on the side of caution.
Partial VIN code is 11k190995
Engine Code is V04O5CGC
Casting Code is 3970010
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Old 11-12-2017, 02:43 PM
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Quote:
Originally Posted by Baldr333 View Post
Ill get the casting numbers for the heads when I can, but I may need to order new gaskets to be on the safe side when I take the valve covers off. They're replacement valve covers for sure, but I'd rather err on the side of caution.
Partial VIN code is 11k190995
Engine Code is V04O5CGC
Casting Code is 3970010
The engine code tells that this engine is was built in Flint, Mi., April, 1970
The CGC suffix is either a police with manual, or El Camino with automatic as 245 hp, 2 bbl carb engine. The difference between this and the 300 horse version is only a 4 bbl carb.

The 010 block casting is a 4 inch bore casting for heavy duty truck, industrial, and high performance applications.

The heads that are on these would establish the compression ratio.

Bogie
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Old 11-12-2017, 03:09 PM
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The Weiand X-celerator is a single plane manifold designed to make horsepower power at high RPM. But it will really hurt torque at low-mid RPMs, which is where street engines live. So the first thing I'd do is replace it with a Weiand Street Warrior or Speed Warrior manifold, or Edelbrock Performer EPS or Performer RPM. If you can find a used #2101 Performer manifold or a #8004 Weiand Action Plus, those would work too.

Next, I'd add headers or at least do whatever I could to reduce exhaust restrictions. Depending on which manifolds you have, they could be very restrictive.

Finally, ignition timing is everything. I'd suggest starting at 12 degrees advance at idle with the vacuum advance line plugged. Then another 23 degrees (for a total of 35 degrees) maxed out at around 2500 RPM. You will probably need softer springs to achieve this, unless the PO already did it (unlikely). And the numbers above aren't gospel.

Only then should you reconnect the vacuum advance and check to see that you're getting an additional 10 degrees or so at idle. If you see another 20 degrees instead of 10, well that's an emissions era vacuum canister, and has all kinds of drawbacks. But hey, there's tons of info on the web about ignition timing.
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Old 11-12-2017, 03:14 PM
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Quote:
Originally Posted by BogiesAnnex1 View Post
Quote:
Originally Posted by Baldr333 View Post
Ill get the casting numbers for the heads when I can, but I may need to order new gaskets to be on the safe side when I take the valve covers off. They're replacement valve covers for sure, but I'd rather err on the side of caution.
Partial VIN code is 11k190995
Engine Code is V04O5CGC
Casting Code is 3970010
The engine code tells that this engine is was built in Flint, Mi., April, 1970
The CGC suffix is either a police with manual, or El Camino with automatic as 245 hp, 2 bbl carb engine. The difference between this and the 300 horse version is only a 4 bbl carb.

The 010 block casting is a 4 inch bore casting for heavy duty truck, industrial, and high performance applications.

The heads that are on these would establish the compression ratio.

Bogie
Guess I was a year off then. So with the aftermarket Edelbrock 4 BBL it would more than likely be making 300hp or whereabouts? I'll post when I have the head casting codes as well to figure out compression ratios a bit better. Also looking to test compression anyways. Thanks!
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Old 11-12-2017, 03:18 PM
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Quote:
Originally Posted by 55_327 View Post
The Weiand X-celerator is a single plane manifold designed to make horsepower power at high RPM. But it will really hurt torque at low-mid RPMs, which is where street engines live. So the first thing I'd do is replace it with a Weiand Street Warrior or Speed Warrior manifold, or Edelbrock Performer EPS or Performer RPM. If you can find a used #2101 Performer manifold or a #8004 Weiand Action Plus, those would work too.

Next, I'd add headers or at least do whatever I could to reduce exhaust restrictions. Depending on which manifolds you have, they could be very restrictive.

Finally, ignition timing is everything. I'd suggest starting at 12 degrees advance at idle with the vacuum advance line plugged. Then another 23 degrees (for a total of 35 degrees) maxed out at around 2500 RPM. You will probably need softer springs to achieve this, unless the PO already did it (unlikely). And the numbers above aren't gospel.

Only then should you reconnect the vacuum advance and check to see that you're getting an additional 10 degrees or so at idle. If you see another 20 degrees instead of 10, well that's an emissions era vacuum canister, and has all kinds of drawbacks. But hey, there's tons of info on the web about ignition timing.
I'll look into replacing the intake manifold ASAP. Was actually reading into the Edelbrock performers recently, intending to possibly replace the X-Celerator anyways. As far as headers and exhaust go, I was planning on hooking up some full size tube headers with a dual exhaust set up as soon as I could. Timing I'll have to read up on more, as I'm not familiar with most of that, but it's good to know I have something else to familiarize myself with. I'm always down for learning as much as I can and expanding my areas of expertise a bit. Thanks for the info man
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Old 11-12-2017, 03:29 PM
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Quote:
Originally Posted by BogiesAnnex1 View Post
The engine code tells that this engine is was built in Flint, Mi., April, 1970
The CGC suffix is either a police with manual, or El Camino with automatic as 245 hp, 2 bbl carb engine. The difference between this and the 300 horse version is only a 4 bbl carb.
Are you sure? I'd almost bet compression for the 300 hp engine is higher, and the heads may be different, too..

OK, just found these 1970 specs at novaresource.org. Notice the compression. I'd guess the 300's valves sizes are bigger too, and possibly the heads.

1970

350 V8 L65, 250 hp @ 4800, 345 lb/ft @ 2800, 9.0:1
350 V8 L48, 300 hp @ 4800, 380 lb/ft @ 3200, 10.25:1
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Old 11-12-2017, 03:53 PM
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Quote:
Originally Posted by 55_327 View Post
Quote:
Originally Posted by BogiesAnnex1 View Post
The engine code tells that this engine is was built in Flint, Mi., April, 1970
The CGC suffix is either a police with manual, or El Camino with automatic as 245 hp, 2 bbl carb engine. The difference between this and the 300 horse version is only a 4 bbl carb.
Are you sure? I'd almost bet compression for the 300 hp engine is higher, and the heads may be different, too..

OK, just found these 1970 specs at novaresource.org. Notice the compression. I'd guess the 300's valves sizes are bigger too, and possibly the heads.

1970

350 V8 L65, 250 hp @ 4800, 345 lb/ft @ 2800, 9.0:1
350 V8 L48, 300 hp @ 4800, 380 lb/ft @ 3200, 10.25:1
Correct me if I'm wrong, but 71 350s were cast in1970, and the suffix would point back to 1971 vehicle applications, so I would have to look at specs for the 71 engines, correct? Though it was cast in 1970
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