I usually come up here with input on our 'higher-end" units forgetting sometimes not everyone is looking for this type of setup. We just had kind of a different request for a build as it says above, a 396 BB built around the "budget-only". Not caring about HP or Torque numbers whatsoever. The customer left the choice of parts up to us with only one exception, he wanted the results to include any type of "cast" pistons. We figured it was the perfect choice to test the KB160's, we've never used a "hyper-eutectic" in any testing before this time. The weight of the piston was a factor in the choice. Weight-wise we considered it an "equal-replacement" piece (kind of heavy). Once in a "blue-moon" we'd sell a set of these, but have yet to "test" any.

As I stated above, there was NEVER an HP/Torque number mentioned. But we were very curious. What we were handed was an all-original 396/325 HP oval port unit. Block casting #3916323 (2B.M.), Cast crank, 3/8" rods, cast 10.25 pistons, and a pair of factory #3917215 "oval" port heads. We had no intake for this unit, so the customer and I agreed ahead of time to use a "Performer" figuring it would fairly close to original. We said nothing to the customer during the build/test, but what we were really most interested in besides the pistons was the "fuel-consumption" results.

The only two parameters we were "locked" into was the C.R. had to be around 9.0:1 (final was 9.2) and absolutely no "tricks", this was the customers wording, not mine. In simpler terms, there was to be no excessive milling, no gasket matching, definitely no porting (including any bowl work), this was a good ol' "down & dirty" rebuild, nothing more. Stock valve sizes, no "light" stems, no back-cut angles, had to use stock rockers, and stock valve covers.

After writing the order, but before we starting the program, we envisioned an "RV"/truck style unit with corresponding HP/Torque numbers that would probably be able to achieve some "decent" gas mileage. We haven't done a unit "down" at this level in a very long time. The best thing is we were getting paid to go through it all, it wasn't us "digging" in our own pockets this time for answers to questions about products we really weren't concerned about!

Here's a list of components, the dyno "numbers" follow:
Pistons: KB130's
Rings: E243K's gapped at .030" top and .022" second.
Bearings.: Clevite's mains-.020"s F/M's rods-.010"
Oil System: Stock pan/screen, Melling pump #M77 w/M77020 HPspring (Idles @ 25#, runs @ 55#)
Cam/Lifters: Blue-Racer "hydraulic" 214* @ .050" x .500 x 114 L/S (In @ 109 C/L) / Johnson #817's
Gaskets: Corteco's #32377CS
Valves: G.M. Stock 2.060" and 1.720". No back-cuts (seats located at outer edge however).
Springs: G.M. Stock "singles". Customer's choice, we recommended dual's. Pressure’s at 110# / 285#.
Rockers: G.M. Stock "stamped" with a set "slotted" balls and new lock-nuts (16 new studs also).
Fasteners: All stock, the original's were retained.

Unit came off the dyno at 362 HP @ 5650 and 420 Ft.Lbs. Torque @ 4100. We tested this with the only headers we had available at the moment, which were 1.750", and a 750 Holley. There was absolutely no "traces" out the exhaust ports. Everything seemed fine and it's been delivered. Thanks, Gary in N.Y.

P.S. The unit probably would have benefited from a 650 Holley and 1.625" pipes but the customer was satisfied! Block was most definitely "block-plated" AND line bored. We replaced a single cap that was loose in the register. This was one "thin" casting. I put this post here as I said because we know not everyone is looking for "race" only units AND there are "budget-minded" customers. I'll get fuel readings and add'l info from the customer about the vehicle at a future time. The fuel flow meter showed some unusually low numbers. There’s a copy of this on the Camaro site also.

How smooth was the idle?
What rpm did it idle at?
Did you check the vacuum at idle? How much?
What was the total timing on the dyno run?
Very interesting, hate to say it but with fuel prices this kind of build is going to picking up in popularity. Thanks for the info.

those are good #s for that engine. I wonder what a similar 454 would pull?

Seems in line with what you would expect from a fresh 396. Cam specs were basically replacement 395/350HP cam. Little confuesed on what pistons and final CR you got, you listed two different pistons in the post. My 402 was rebuilt using TRW L2354's which is the stock piston for the 396(402) 350HP motor.

Those are good solid #'s for a very mild 396(now 402) but i am really surprised that a 402 with only 214 deg dur@.05 on a 114 deg L/S tops out at 5650rpms which seems high for that cam.

I would think that motor with such a mild cam would be all but done rpm & power wise at approx 5k-5200 rpms top with that mild of a cam in it.

The cam you used is very close to the stock GM 986 L34 396/350hp hyp flat tappet cam which was 214/218 deg dur@.05,.461/.480 lift,115 L/S angle but was running in later yrs with a q-jet on cast intake with more comp @ 10:25:1 and topped out at approx 5200rpms with 350hp & 415 lbs trq and your #'s were 362hp & 420lbs trq.

You got 12 more hp with 5 more lbs trq with less comp but at a higher rpm with approx same cam with a smidge more lift with maybe a much better newer lobe design that would explain the higher rpm for such a mild cam.

Scott

Good thread!

Imho, build it mild for grunt AND it should be eff. too!

pdq67

How smooth was the idle?
What rpm did it idle at?
Did you check the vacuum at idle? How much?
What was the total timing on the dyno run?
Very interesting, hate to say it but with fuel prices this kind of build is going to picking up in popularity. Thanks for the info.

Hi sleeper, unit sat and idled like "pussy-cat" in the 700 range, maintained 16+ inches vacuum at idle, had 14 degrees on the tag and 37 degrees on the top side. We were "sweating" the single springs making the RPM's, but it went fine. The "small" valves were a help there. The larger 2.190's/1.880's probably would have been bouncing all over the place.

I would like to add that there's probably some add'l 25/30 HP in this unit with a lighter piston, the KB's were at 640 grams, and a "custom" valve job. The 2362 gram "bob-weight" on this unit was about 80 grams heavier than our 540's at 2282! Not to mention there was no "flogging" in the dyno room. I'm certain we could have pulled a few more "ponies" out if we had really tried. Thanks, Gary in N.Y.

P.S. As I said in the beginning, this was a total "customer-dictated" build. We were merely his "tools". I believe he's going to build a few of these same units and "off" them. I also believe the fuel prices fall into his program somewhere. The unit should pull down some decent mileage for what's in it.

Pretty stout motor for "just a rebuild". Out of curiosity can you recommend any pistons for a '72 402 with the stock open chamber, oval port heads? It's kind of tough to find slugs for these in any good (9-10:1) compression with their large ~118ish CC heads. Seems like my choices are 8:1 or 12:1 using stock pistons, looks like custom cut are the only good option to get what I want.

Pretty stout motor for "just a rebuild". Out of curiosity can you recommend any pistons for a '72 402 with the stock open chamber, oval port heads? It's kind of tough to find slugs for these in any good (9-10:1) compression with their large ~118ish CC heads. Seems like my choices are 8:1 or 12:1 using stock pistons, looks like custom cut are the only good option to get what I want.

Hi Superchevy, you should be able to use an L2242F TRW forging and get where you're looking to end up! Depends entirely on your budget. Those particular heads should come in around 114 cc's. We used the same castings on the LS-5 we just tested. The '72 402 uses the same style, it should have an unshrouded section by the exhaust valve. Probably a #292 casting. Thanks, Gary in N.Y.

P.S. The L2242F's would have to be checked closely for P/H clearance. There may be some "massaging" involved, but they should work!

What was the final cost of the build?

Interesting and I'd like a ballpark for the cost too....

I have a 69 396 going into my 66 SS (someday) and need to get it rebuilt also. I believe the heads were 325 hp from decoding them on mortec. the engine is the block with the inners and the heads and water pump. I need everything else such as carb & manifold, ignition system and starter... probably need a new water pump or rebuilt the one I have...

I have a local builder that I trust with the engine but want to be more educated and possibly walk in with some suggestions.