[against all odds]

Let's assume we have a good aftermarket/or higher end production block----i.e., bowtie, dart etc.

Having that in mind, how would build an sbc to achieve maximum power naturally aspirated?


Parameters:

1) Must have good idle quality---let's not get too wild on the cam.

1a) Must be easy to start.

2) Get it as light as possible, so alum heads, but this is not manditory.

3) We can go to 400 inches or higher because those blocks can accomodate that.

3a) Must be naturally aspirated.

4) Working budget, say 10K. But the blocks are at least 2K, so really the budget is now 8K.

[against all odds]

Whoops, let's start the parameters over(can't edit):


1) Must be easy to start and have good steady idle; Must be able to put in gear with a tight stock converter and revved up against the converter and not stall. Let's stay conservative on the cam.

a) Even though the intended application is dragging, the engine must past this theoretical test: It will be installed in a large truck and/or 4x4 vehicle. It will then be driven up a very steep hill OFF IDLE and must not only not stall out but easily drive up the hill briskly with 2.56 gears.

If the engine makes more low-end torque vs. higher end HP that is ok.

2) Operating range is idle to 5000 rpm, BUT if the reciprocating and valve train assemblies can take it then if we can go above 5000 with no problems then fine.

3) If we need to go to 400inches or more that it is fine.

4) i would like it as light as possible so alum heads is highly desired, but not manditory.

5) Naturally aspirated only. (for now)

6) total budget is 10K, but the least amount of money spent would be the target.

[ap72]

Sounds like you are wanting to build a race engine and drive it in a tow truck. For 10k do yourself a favor and build a BBC, and id look into a good efi system too. A 454 bbc can make much more power than a 454 sbc.

[Greg T]

Originally Posted by against all odds

Let's assume we have a good aftermarket/or higher end production block----i.e., bowtie, dart etc.

Having that in mind, how would build an sbc to achieve maximum power naturally aspirated?


Parameters:

1) Must have good idle quality---let's not get too wild on the cam.

1a) Must be easy to start.

2) Get it as light as possible, so alum heads, but this is not manditory.

3) We can go to 400 inches or higher because those blocks can accomodate that.

3a) Must be naturally aspirated.

4) Working budget, say 10K. But the blocks are at least 2K, so really the budget is now 8K.

Well, do you actually want a "max power" build or do you want to stay withing the parameters you've set? Ya can't have both.

[against all odds]

Maximum power within the set parameters.

[against all odds]

Ok, well i'll give it a shot then:

1) Bowtie race block #24502503. $2830+$100 shipping = $2930

a) Align-bore, honing and i'm not sure what other machining needs to be/should be done. $$$??? Also, i'd like to open the cylinders up to 4.100" or more if possible to get at least around 400cid. More $$. But if this sacrifices reliability then forget it. (comes with 3.980" bore but can be opened to 4.155" max.)

2) Complete Scat all-forged rotating assembly. This is with 3.750" stroke $1600 +$8 shipping due to weight. Also i'm not totally sure of the dish vs. flat pistons, I vs. H beam rods and all that other jazz, but the price will be similar if not identical if we need to swap out components.

3) Clevite 77 (or equivalent) cam bearings. Should not be more than $50 free ship

4) ARP head studs. Not sure exactly which ones to get but should not be more than $230 w/ free ship.

5) Cometic (or equivalent) head gaskets. Should not be more than $130 w/ free ship.

6) Comp cams #12-206-2 (the 260H series) cam. Specs @ .50" are 212 deg intake, 212 deg exhaust. Remember, we DO NOT want something too wild and choppy and hard to start. And we want it to be able to idle well with a stock converter.

i would prefer a roller cam with similar specs. i do not know what the equivalent specs would be because roller cams act differently than flat lifter cams. i also do not know what it takes both money and physical modifications (if any) to run roller lifters. But a complete kit including roller lifters and cam should be not more than $300. A complete valvetrain kit---timing gears, chain, rockers, pushrods, cam, rollers etc. is around $1050.

If the roller does not provide substantial increase in power over a flat(like at least 50hp), then we should stick with flat to try to keep the costs down. Right now, i'm figuring in the $1050 for the complete roller valvetrain kit.

7) ATI super damper harmonic damper. 7" Should be no more than $250 for a small block. Free shipping.

8) GM 14044872 oil pump. $82 free ship. Is a hi-po, high volume pump really nessesary in this case? i don't know.

a) Milodon street/strip deep sump oil pan. $183 free ship. Holds 7 quarts.

9) For heads, i like the aluminum vortecs. $1220 pair. Probably some shipping charge.

An easy (though usually not cheap) way to go faster is to keep the weight down, so i'd like to go aluminum with the heads. If they make an equivalent to the Sportsman 2 heads in aluminum i would consider that.

10) i would like to eventually go with a dual tunnel ram, but since i can barely tune one carb much less 2, let's go with edlebrock performer rpm (hi-rise) intake and quadrajet. $205 including gaskets, intake bolts, free ship. i already have a quadrajet 750 cfm sitting on the shelf, but if not then we should figure about $400 for a decent rebuilt one. This could vary quite a bit because you could find a decent used one a rebuild it yourself.

11) GMPP stock HEI distributor. $147 free ship. i think decent, workable units could be found at the salvage yard for much less---maybe $20.

a) Accel super stock plug wires. $32 free ship.

12) i think a stock fuel pump, pushrod, and fuel line could be used because we don't need high fuel pressure here? $70 or less could be picked up at autoparts store and/or salvage yard. i actually have most of this sitting on the shelf.

13) Hays/tci/ or equivalent flexplate. $75-90 free ship.

So, about $8077 without any machine work. i've probably left a few odds and ends things out.

Also, i'm pretty sure there is an intricate, crucial and vital relationship between piston shape, head chamber, compression and cam and i don't know jack about it. i have no idea what compression would be on this engine. But i'm thinking on a naturally aspirated engine the more the better.

[Landshark928]

So many combinations... Here's one that runs fine on 93 octane

Dart SHP block 400 $1500
Scat 9000 crank, forged rods and Probe forged pistons(7cc). 10.7:1 $1000
HYD roller cam and lifters .640 lift 254/254 @ .050 $600
DrJs Airwolf 220e heads (flow 310cfm/220cfm @ max cam lift) $1600
Air Gap RPM intake $250
Scorpion 1.5 rockers $225
Powerjection III fuel injection $1600
Electric water pump and fan $200
1 3/4" long tube headers $350

Should make right at 575-600HP and 500ft-lbs+. Fuel injection and dual plane intake will help control the idle, make easy starts and help low rpm performance. This is similar to what I run. Bryce at DrJs made 640HP with these heads and cam on a 11.5:1 procomp block 400 with a ported Vic jr.

If you do the work yourself, you can build this engine for about $8K+/-. You can shave a grand off by going with a carb.