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.

 

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

 

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

 

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?

 

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

 

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

 

The 1971 245hp 350 is 8.5:1 compression with dished pistons and 76cc heads. My mother had a 1971 Chevelle I talked her into buying new in 1972 that had one of these motors. Beautiful car. Copper brown with white stripes and white buckets/console but not an SS. I was 16 years old and it was a great car to borrow to tool around in.

If your bottom end is solid and you want to make some decent power without killing driveability, the best thing you can do for it is to get the compression up some with some modern 65 cc aluminum heads like Pro-filer 185cc, get rid of the single plane intake and go to something like Edelbrock Performer RPM (not air gap), and get some decent small tube headers. Find out what cam is in it as you need one that will not kill your dynamic compression.

Typical novice builds have large chamber heads, dished pistons, and too big of cams for the compression ratio - and this sound like what you have. Does it idle smooth or does it lope?



.

 

I'm new to this, but lopey idle is where the RPM bounces a but during idle correct? It idles smooth at a constant RPM as far as I can tell. What am I looking for exactly?

 

3986339 stock heads. 1.72 intake/ 1.5 exhaust

 

Junk, as far as any performance goals are concerned. Very small valves, poor combustion chambers.

Best plan on a head swap.

 

Also looks as if the rocker arms and springs are extremely clean, possibly redone at some point, or just fantastic condition for a '71

 

I’d definitely decide what you’re doing about the heads before you buy an intake-unless you get a good deal and can resell it later. Some heads like the l31s use a different bolt pattern


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I?d definitely decide what you?re doing about the heads before you buy an intake-unless you get a good deal and can resell it later. Some heads like the l31s use a different bolt pattern


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I think I'll stick with stock heads for now, get a dual plane Edelbrock intake more fitting to my RPM range, and then add headers and a dual exhaust and maybe do more down the line.

 

Is a decent imported aluminum head bought bare then fitted with parts from a good source, at about the $550 price point cheap enough??

198-200cc intake port volume, 64cc chamber that will raise your stock low compression about 1.2 points, 2.02"/1.6" valves. Heads will easily make 440 hp with the right parts under them with a cam change and headers on your existing engine I'd expect 375 HP easily in a nice driver.

If so, just ask and I'll PM you a link to the heads and the valvetrain parts kit..

 

Yeah, that sounds good to me. If you could send me that link it'd be much appreciated.

 

About a year ago I built an engine for a customer that wanted a mild streetable build with more of a focus on the show truck he was building and less on the engine/drive line.

The original vehicle he was restoring was sold to him as having a good 350 in it, but when checked it was a 305 that was well worn out. Below I put a list of what we picked up to do the build.

I found a used 350, had the machine shop bore it over .030, and traded out the iron heads #624 for a set of #113 Aluminum Corvette heads I had sitting in the shop.

Intake / carb was a Edelbrock Performer intake and Edelbrock 650 electric choke carb. Ignition was basic HEI, fuel was stock mechanical pump.

Exhaust was done locally, which consisted of shorty headers, cat back 2.5 inch pipe and Flow Master Mufflers.

Along with the engine we rebuilt the 700R4 adding the Z-Pack Clutches and the Corvette Servo.

Parts for the engine are below, prices are approximate. The machine work was about $250, and the heads I already had. If we had to source the heads that probably might been another $600 to $800.


Small Block Chevy 305/350 Mild (Budget) Build

Sealed Power SLP-KC-1014R (1400-4000 RPM)
Adv Lift, 1.5 Rocker 0.420 int./0.443 exh.
Adv Total Dur. 278 int./288 exh. $112.00
Cloyes Dbl Roller Timing Set $32.00
Main Bearings $28.00 Rod Bearings $31.00
Gasket Set Includes Head Gaskets and valve seals $36.00
Sealed Power +30 Flat Top Hypereutectic Piston Set $108.00
HV (High Volume) M55HV Oil Pump $36.00
Steel Oil Pump Shaft $10.00
Taylor Cut to Fit Wires $60.00
Wire loom Set $40.00


$493.00