Question For The 350 Experts

Here's the situation:
We have a 1971 Monte Carlo, with a factory 350, 270Hp engine that has 135K miles on it. When disassembled, we found no spun bearings, but the main was "thin" (no, I didn't Mic it). So we are rebuilding the engine.
I want this engine to be a balance between gas economy and horsepower.
Right now, we're having the block cleaned, bored/honed (probably to .030 over) and the cam bearings, oil gallery plugs, and freeze plugs replaced. I am told after the block is done, to expect a 9.5:1 CR.
We are on a budget, so we can't do everything at once.
The goal is to get the block done and back in my garage. We'll do the heads later.
We are planing on re-using the rods and replacing the pistons/rings/bearings, etc. later with a Master Engine Rebuild Kit.
In talking to my Machinist, he recommends a beefier cam over stock. He recommends a .450 lift cam (no, I don't know the duration or overlap), and replacing the original springs (worn out) for the beefier cam. Lifters will be replaced as the originals are worn out anyways (concave faces).
We had recently had the stock TH350 tranny rebuilt with a "heavy duty" (slightly hard shifts but no chirping tires) shift kit installed. The tranny has performed well. The torque converter was replaced (no, I don't know what the stall RPM is).  
If I have to get the above unknown info, I will.
I am thinking an automatic tranny has a lower power band requirement.
The stock heads will be rebuilt, no porting, new intake and exhaust valves, guides and seals.
I plan on using the original intake and 4 barrel Rochester carb (new).
My question is, will this configuration produce an engine that will yield more than 270Hp?
I've read that a well built engine will yield 1.1 Hp/Cubic Inch.
This means: 350 X 1.1 = 385Hp
Is this plan and expectations realistic?
All replies are appreciated as I only get to do this once.
Jogasz28  
Jogasz28
1968 RS Camaro
1969 Camaro in Resto
1971 Monte Carlo
1995 Monte Carlo

put in a 3.75 crank its not much more money and it will make a big difference in power  

i don't think this engine is very economic but it is dreamy

http://www.chevyhiperformance.com/howto/47075/index.html


el agent 87.

i don't think it will be overly un-economic tho because the heads are very efficient , the cam isn't even big enough to need an after market converter , its just one fine combo. adding an eagle stroker crank to this combo would be very very very intresting.  

buy an afermarket set of heads instead of dumping money into your old castings you can do it for about the same money.  As far as the cam goes i would get the rest of the specs and let us know what your converter is and we will get it figured out for you.  

im with smoke,get some new vortecs with the money you would spend to rebuild them.  

Hi there,
   If I did it again I would use Performer + 180 heads and 222/222* 450/460*
   cam 112* which works O.K with 1900 converter with 3.3 diff. Timing is best
   with 10/1 comp 10*TO 38* and NGK 5's @ 40/1000",. 2 cents worth.. Skyeking  

Ya aftermarket heads would be your best bet.  
Horsepower sells Engines and torque wins races.

I appreciate all the replies.

I'll work on getting the cam/torque converter specs this week.

Thoughts, Questions, and Concerns:
Please bear with me.
I've totaled the cost to rebuild the original heads including
parts and labor and it comes to about $400. This includes heads
degreased, valve grind, new valve guides, exhaust and intake valves,
and new springs (for the 450 lift cam) installed.
I searched and found a cast iron Vortec head selling for $312
each(?). So two Vortec heads would be $624, and wouldn't I also
need to buy an intake manifold as the original 4-Barrel "snowflake"
intake won't match up to the Vortec heads?
I searched for the intake and found the following kit that has the
heads, intake, gaskets, and bolts for $964:
http://www.jegs.com/i/GM-Performance/809/12558060K/10002/-1
Then, will the "new" (just purchased 2 months ago) 4 Barrel Rochester Carb
fit on the new Vortec intake?
Originally, to rebuild the engine back to stock, was going to cost
about $1100 (parts and machining), with my Son and I doing the
disassembly and reassembly.
Obviously going with Vortecs will cost more. But will it add HP at the
expense of economy and long term reliability?
Lastly, I have the original dealership paperwork/ProtectoPlate for this car,
so it does have full Documentation. Changing the engine configuration
concerns me. I know I'll keep the original heads anyways. But I'd hate to
add anything that will stress the engine,shorten it's life, or do damage.
All opinions and replies are very much appreciated.
jogasz28  
Jogasz28
1968 RS Camaro
1969 Camaro in Resto
1971 Monte Carlo
1995 Monte Carlo

Are you installing larger valves? If not why replace them? Whats wrong with them? Valve job,bronze guide liners,resurfacing the heads and some new springs should run you about $325[at least where I live}. Having your block bored .030 over isnt going to get you a 9.5:1CR because most cheaper aftermarket pistons are going to be .040-.050 down the bore unless your planning on decking the block. Are you resizing the rods to with aftermarket rodbolts? Using vortec heads and a 383 rotating assembly with the right cam,intake and headers makes a nice streetable engine with plenty of power for most. Fuel economy has more to do with the driver in a engine like this than the actual engine.  

Thanks for the reply.
Valves are original, and valves/guides were oil-fouling 3 cylinders. As the intake/exhaust valves are around $60, it seemed like a "while your in there no brainer" to replace.
Block is being bored, honed, and decked if needed. Not began yet, so can't answer.
I specified the use of quality Brands. Nothing cheap.
Rods are going to be re-used if possible, new pistons and rings. I haven't discussed the particulars of pistons & rods as we haven't got that far...but I
will soon.
It seems like a 383 crankshaft and Vortec/Intake Manifold/Carb(?) setup will add, if not double the budgeted cost of the rebuild.
I'm trying to stay close to original budget. If I can't, I understand.  
Jogasz28
1968 RS Camaro
1969 Camaro in Resto
1971 Monte Carlo
1995 Monte Carlo

the cost of going to a 383 is only that of the new crank all of the block clearancing is simple since it is already being machined.personally i feel theese days with the cost of building a 383 being within a couple hundred bucks of a 355 there is no reason not to do it  

You don't have to go with vortec heads, look at Summit they have some wery reasonably priced heads.  What are the casting numbers on our heads?  I don't think 385 hp is to expected with that small of a cam and stock heads.  

Using a longer-stroke crank is no holy grail to horsepower. There is no magic involved, changing one variable changes a dozen others - if you can compensate then you can make more power.

More displacement puts more strain on the induction system and requires more available valve curtain area. Making a 383 out of an engine using 305 heads and a ancient, cheap, slow flat tappet grind is a recipe for disaster, for example.  

+1

it is all about the combo.  

No offense but unless your buying Ross ,JE or something along those lines then expect your pistons to be down in the bore about .050. Replacing valves just because your doing a valvejob is a waste. However if they need replacing for whatever reason[worn stems,thin margain,etc] or installing oversizes thats different. Sounds like all you need is a Comp 268 cam and your comp. brought up by whatever means your machinist decides.