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Discussion Starter · #1 ·
Would the standard, Mellings RV cam work with this setup ?

60s chevy pick up
350/350
2 barrel, OEM 2barrel intake
Shorty Headers
882 heads
Flat top or dish pistons
HEI Dist
3:73 rear end gearing

If not , what would be a better option , for a "stock" running engine with fuel economy in mind? Thanks
 

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That cam would probably work fine with the stock setup,. However, it would work a lot better with something like an Edelbrock Performer EPS intake and an Edelbrock AVS 2 carburetor. They should make the most out of those (limited flow) 882 heads.
 

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I've seen similar Edelbrock and Summit 204/214 cams awaken even a base Goodwrench 350 engine with crappy heads and 7.9:1 compression. I mean we're not talking about a huge amount, but you will notice more power in the RPM range where that 3.73 will put you in everyday driving. And a 500-600cfm 4-bbl carb would only add to that, and bump usable RPM by 500 or so. Wouldn't surprise me if that combo picked up 10%-15% torque and horsepower over a stock cam with 2-bbl carb. Guys, am I being optimistic here?

Dual exhaust are a must, even with stock exhaust manifolds! 2" pipes would be fine, but 2-1/4" preferable. And crank in a little more initial spark advance than stock, as well as total advance (initial + centrifugal with vacuum advance port plugged). You can Google that to get a ton of info.
 

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Would the standard, Mellings RV cam work with this setup ?

60s chevy pick up
350/350
2 barrel, OEM 2barrel intake
Shorty Headers
882 heads
Flat top or dish pistons
HEI Dist
3:73 rear end gearing

If not , what would be a better option , for a "stock" running engine with fuel economy in mind? Thanks
The stock cam times 196/204 that was used in all pre 1987 V8’s as standard production for 2 and 4 bbl V8’s. It actually harkens back to the 327 if not the 283. The cam was standard fare up to the 300 horse 327/350 engines. The 350 traded 48 more cubic inches for about a ratio and a half less compression compared to the 327 to deliver the same horsepower curve.

Shorty headers do nothing or at least close to nothing compared to cast iron manifolds except spending money for them. Dual exhaust for cast iron manifolds is about the same improvement where unless you drive winding the engine out all the time is really not a noticeable improvement. This is a function of mass flow through the engine where basically unless it is operated continuously at full throttle there just isn’t enough mass exhaust flow to crowd the stock exhaust system to its capacity thus for ordinary driving back pressure pumping losses are minimal at most and unlikely to be significant. That said, the change to long tube headers and either duals of a large diameter single can help in that long tube and tri-y configurations do use and benefit from pulse timing which often pulls the mid range torque up several foot pounds which is right where it’s needed for street operation which then allows maintaining speed with less throttle which rewards you with a small mileage improvement. They also have great power improvement but again that is mostly seen on the top end where your not usually operating. So of most anything long tube headers offer the singular best chance of seeing a mileage improvement for the money spent. Short tube headers in spite of looking streamlined and thusly appear efficient really offer little to nothing till the engine is operated approaching peak RPM again a mass flow issue.

882 heads are low performance, low compression, poor burning, fuel hungry heads more or less standard GM SMOG era stuff. Swapping to a modern head will improve power and mileage. Here again for the dollars spent the power gains of heads like the L31, Vortec are spectacular while the mileage improvements without Electronic Fuel Injection (EFI) and an overdrive transmission are not significant against the money spent.

Flat top pistons would boost the compression compared to round dish pistons but with 882 heads this increases the risk of detonation which will drive you into spending your money on premium fuel.

HEI is a decent swap to reduce ignition system maintenance i.e. no point wear forcing replacement and tuneups. From a mileage standpoint against a set of good functional points there is no benefit. Additionally HEI runs on full time 12 volts where points only use full available battery voltage (B+) during cranking while in normal operation get fed 6 to 9 volts through a resistor. GM used two resistor schemes one an external on the engine or firewall that is easily jumpered to supply full time B+ to the HEI the other is a resistive wire between the ignition switch’s RUN terminal and the points coil, this is more of a pain to rewire for supplying RUN full B+ voltage to the HEI.

All in all your suggested changes will do little to nothing to change fuel mileage and are likely to drive you into premium fuel. The HEI aside I see no gain in mileage or power here but there is a reduction in required servicing. The simple fact is that it is technically difficult to improve fuel mileage without spending more money on parts and components that can be recouped through mileage improvements.

Probably the most effective way to improve mileage that doesn’t cost an absolute arm an leg compared to the gains is to swap the much shorter lobe timed flat tappet cam used in the 305/350 truck engines from 1987 through 1995 Swirl Port headed, TBI engines. This cam removes 20-30 degrees duration from the cam you have. Power will go down but mileage creeps up a little. This cam is really intended to work with the Swirl Port heads; of that era the casting ending in 193 being the most desirable of these undesirable heads for a big power stand point these have a semi active combustion chamber which except for one feature is the same chamber as used in the L31 Vortec head, it however, does not use the L31’s intake porting. But while these heads use the 6 bolt intake attachment pattern the center 2 bolts repose at a different angle to the machined face of 72 degrees instead of the classic 90 degrees so without bolt angle modification to either your intake or to the heads there is a miss fit between intake and heads. As usual while this is probably the best combination to increase fuel mileage at minimal if any change in power again the cost of the change against the delta fuel mileage savings it takes a long time to financially break even let alone start getting ahead.

So to make any changes that come close to having financial break even in your’s or the vehicle’s life time is nye on impossible. If all you’re doing is wanting to chase power improvements the answer of cost against desired improvement is way different. Mileage improvements per dollar spent are much harder to justify. That essentially takes a whole vehicle approach which is why modern vehicles starting about 1987 are so fundamentally different than those before 1987 in their operating systems.

Bogie
 

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I'm going to take exception with Bogie's comments about dual exhausts making no difference with a stock engine and cast iron manifolds.

Some of you may have heard me mention this experience: When I got my 69 C10 30+ years ago, it had a stock 307 with single exhaust and got around 10-11 MPG combined. I added a Q-jet manifold with a 450 Holley Economaster, along with 2" dual exhaust and generic "turbo" mufflers. Those were pretty crappy heads, but mileage went up to 13-14, and the engine simply came to life. I mean, it was like a different truck.

Also, back in the 60s, all 283s and 327s with 4bbl carbs got dual exhaust as standard equipment Even the lowest horsepower models, like the 220hp/283 and 250hp/327. And that was with the same cam as the 283 2-bbl, and I think even the same heads.
 

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dont put even a penny into 882 heads, stock GM cast iron 4bbl intake with edelbrock 750, dual exhaust 2 1/2", cam with around 204º intake duration with .400 lift and L31 heads
mileage will be good and power decent
 

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Discussion Starter · #9 ·
Thanks Guys , for the great help coming from your experience. Unfortunately, at the moment we are looking to get the truck running in basic form but not set it up for complete failure. No future drag runs for this truck , just old man put putting around but again dont want a full on terd either. The truck currently has long tube headers , hooker , but the clearance under the truck is the main issue and reason for the shorties. The truck has a 2-4 inch drop in stance.
 
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