Could somebody Translate this upgrade to an L48 engine and what I might expect as far as horsepower, performance, reliability, gas mileage and general opinions

 

From my perspective, there is just not enough info to really guess - You would want to know the specs/part numbers used on the engine to even guess> I would want to know what specific heads/cam were used (i.e., specific part numbers to determine runner sizes, combustion chamber size, etc for the heads and duration/lift specs on the cam) Also would need piston type (dished, flat, valve relief size, etc). Was the engine a rebuild of the original block or a crate engine?

 

the mods were made to the original L48 engine
and everything you replied pretty much goes right over my head

 

The cam is a 272 Energizer that has a 1600-5400 RPM power range. Needs 8.75-10.00 Compression. Looks like it might be an old Cam Dynamics grind before Crane bought them out.

The heads are more performance oriented. They have even more HP potential in them.

The roller tip rockers are worth a handful of ponies, but not a whole lot.

The true dual exhaust was a big improvement.

Overall, it was a very sensible upgrade that had some thought put into it. My wild azz guess is 300-325 HP. I would want to recurve the ignition, re-jet the carb and call it a day. Should be easy to live with and reliable.

BTW - I also own a red '80 and have very similar modifications. I have Dart Iron Eagle heads, roller tip rockers, true dual exhaust, re-jetted original quadrajet and an ignition re-curve. I kept all the rest stock. The idea I had was to "back date" the engine to "pre smog" 1970 350/350 specifications as close as possible without altering the appearance or functionality.

 

If it were me, I'd be tempted to install the true dual exhaust, then install a "factory engineered/assembled crate motor", with a warranty, and call it a day....

 

one question .. WHATS AN ALDRENATOR ? and why is it chrome?..ok that's 2 questions

 

without the Aldrenator the wishy whippers will quit working

 

Oh... I thought maybe it was where you pour in the BLINKER Fluid

 

OK, I literally laughed out loud and almost spit coffee on my monitor reading this.

 

And they say comedy is dead 😁

 

If you want to know the horsepower the best thing to do is take it to a shop with a dyno and get it actually tested. Even if we knew the rough numbers 15 years of driving may change things.

 

Too many compression ratio-related variables to Know ... actual compression ratio is major determinant of resulting power.

Seems motor was rebuilt & bored thirty-over ... they replaced pistons but who knows if flat or dish or dome ...
... their respective volumes are quite different ... piston volume is major determinant of compression ratio

Head gaskets available in a wide range of volumes ...
... gasket volume is major determinant of compression ratio.

Seems motor was rebuilt and OE cylinder heads were replaced with Edelbrock Performer RPM heads ...
... those heads available with at least two different combustion chamber Volumes ...
... combustion chamber volume is a major determinant of compression ratio.

We don't know which piston volume nor which gasket volume nor which chamber volume so we cannot estimate compression ratio.

But I'll make a WAG ... a Guess ... they installed the more common/conventional rebuilder parts.
> Sealed Power Flat Top piston pn H345-30 has compression height 1.548" and volume 6.9 cc.
> Most Common composition head gaskets are about 0.039" thick & have volume about 9 cc.
> Most Common aftermarket cylinder head chamber volume is 64 cc.

I GUESS this 355 compression ratio is about 9.3:1

With about 9.3:1 CR, crane 100052 216*/216* .454/.454 cam, decent edelbrock heads and headers ...
... My WAG is ... I GUESS it'll make about 320 - 330 hp on engine dyno on pump gas.

This has a Flat Tappet cam ... if motor was assembled by competent builder ... and it was broken-in properly ... this motor should be very reliable.

 

OP greg

? Is your invoice from a shop in South Florida ?

 

it's amazing what you guys can determine with limited information..... I never expected that much horsepower..... the car ran beautifully 240 miles from Georgia to Florida couldn't even feel the engine couldn't hear the engine only the exhaust temperature stayed under 180..... not sure where the rebuild took place but I bought the car out of North Carolina I'll have to look at the original paperwork maybe I can find out it came with a shitload of papers I haven't gone through yet....

 

Car cost me $9,500 the paint is easly a 9 out of 10 brand new interior brand new brakes and lines car needs major suspension work all the bushings are trashed had a little antifreeze leak on top of the engine a tiny oil leak and a tiny transmission leak but no puddles on the ground just some wetness underneath it needs new motor mounts... also the steering was scary squirrely on the highway but seemed to handle and turn tight at low speed so hopefully I don't have to redo the steering maybe just some tightening and adjustments final word has not come back from the shop yet my goal was to get a car that I can take to shows and that was really reliable for 15 grand

 

 

 

 

also when I turn on the air conditioner I can feel cold air down by my feet but nothing comes through the vents don't know what's going on there

 

OK, maybe I missed something here......

Was the image of the work order, posted in post #1, a shop order for the work that has been done to the OP's car, sometime in the past, or something that was done to somebody else's car, and now is being proposed by the OP, for his car, and he wanted opinions of how it would work for him. I'm a little confused now, and it's quite possible that my initial post could easily be misinterpreted.....