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Discussion Starter #1 (Edited)
Dear All,

I just pulled out my SBC 400 (2-bolt) for a refresher. The short block is stock. I am running AFR 210 Eliminator heads (75cc) and a mild roller cam with a Procharger D1-SC. This dynoed at 460HP @ 5379rpm at the wheels. 8-10 PSI?

This is 95% street driven. For xxxxx and giggles I take it once a year to the track with no real competitive ambition; this is my daily driver. Other than the occasional stoplight dash, I drive like a grandma.

Since the engine is out, I am considering replacing the rotating assembly with a forged one and upticking boost to 12 PSI . (I am also running water/meth injection)

What about the block???? I thought it was good to 4-500 ponies?

What intrigues me is what I read in Procharger’s Chevy catalog, and I quote:

Engine Blocks
Most ProCharged engines are built using production engine blocks. Though they offer many benefits, an aftermarket block isn’t a necessity in a small block producing less than 900 ProCharged. As with any high performance engine build, it is wise to use a block that shows minimal signs of core shift and does not require an excessively large over bore that may weaken the cylinder walls.
What gives????

My question is this is the above Procharger claim flippant? Can I get away with a production block? Anything I should do to the block such as hard block, splayed caps? And if it can take 12 PSI boost, what about max RPM? For the moment on a stock rotating assy I keep it to 5500 RPM.

My block has never been rebuilt and was never abused. Of course, if I rebuild I will have it sonic tested and magnafluxed or equivalent.

One last parameter to this equation, I am in Belgium here – everything I order from US will cost me 30% more… including shipping. An aftermarket block would be quite an expense from over here…

Oh, one last, last option: I do have a 4-bolt 350 in my basement… An option but at the loss of 50 cubes.

Cheerios,

D.


 

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I run about the same setup as you, but I did hardblock the engine and installed splayed caps. I got a deal on the machine work, otherwise I would have done a Dart block. Engine has held up for 5 years, no problem though.
 

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What about all the above with 10.6:1 compression?

I have a very similar setup when compared to the OP and my tuner wants me to put an F2 on it (or the equivalent Vortech) I am worried the block wont last even if I run lower boost.
 

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Used Bowtie block, Dart SHP block or a World Products Motown II, each block can be had for $1200-1500 U.S., so adjust accordingly.

When deciding on what block to start with, you need to really take into consideration all the different machining operations and improvements you plan on making to either the 400-2bolt or the 350-4bolt. The 350 block is generally considered stronger than the 400 casting by up to 200rwhp. If you get machine work done for free, disregard most of what you're about to read.

Complete "Race Prep" at my preferred machine shop is $850, not taking into account the splayed caps, which adds $350-500 parts/labor (I asked at the time of my machine work), or deck plugs (to help strengthen the deck surface of the block) that added $60 to the tally, and Hard Blok for another $40. The Prep price included initial hot tanking, bore, Torque-plate hone, align-hone mains, parallel deck surfaces, clean/chase all threaded holes, replace cold-set plugs, and final cleaning/sanitizing.
After all of this is done, you're still building off of a STOCK block. You're already right at (or past) the cost of either of the aftermarket offerings, each of which features priority main oiling and thicker bulkheads/deck surfaces, always good for power-adder applications. The "power estimates" that you read about for each block are made AFTER all of the aforementioned machining procedures have been completed. The general consensus that I've seen is 650rwhp for the O.E.M. 400cid blocks and 800rwhp for the O.E.M. 350cid blocks, give or take 50rwhp.
I hope this is helpful info', I almost went down the stock-block road, starting with the nicest 400-2 bolt casting I've ever seen. Good luck to you!


---==Temio Williams
Yuba City, CA
 

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I asked because it's how I bought the car. The previous owner had intentions of putting a blower on it, but it never got to that point before I purchased it.
 

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Used Bowtie block, Dart SHP block or a World Products Motown II, each block can be had for $1200-1500 U.S., so adjust accordingly.

When deciding on what block to start with, you need to really take into consideration all the different machining operations and improvements you plan on making to either the 400-2bolt or the 350-4bolt. The 350 block is generally considered stronger than the 400 casting by up to 200rwhp. If you get machine work done for free, disregard most of what you're about to read.

Complete "Race Prep" at my preferred machine shop is $850, not taking into account the splayed caps, which adds $350-500 parts/labor (I asked at the time of my machine work), or deck plugs (to help strengthen the deck surface of the block) that added $60 to the tally, and Hard Blok for another $40. The Prep price included initial hot tanking, bore, Torque-plate hone, align-hone mains, parallel deck surfaces, clean/chase all threaded holes, replace cold-set plugs, and final cleaning/sanitizing.
After all of this is done, you're still building off of a STOCK block. You're already right at (or past) the cost of either of the aftermarket offerings, each of which features priority main oiling and thicker bulkheads/deck surfaces, always good for power-adder applications. The "power estimates" that you read about for each block are made AFTER all of the aforementioned machining procedures have been completed. The general consensus that I've seen is 650rwhp for the O.E.M. 400cid blocks and 800rwhp for the O.E.M. 350cid blocks, give or take 50rwhp.
I hope this is helpful info', I almost went down the stock-block road, starting with the nicest 400-2 bolt casting I've ever seen. Good luck to you!


---==Temio Williams
Yuba City, CA
Well said. We have seen several 400 stock block making power 5's in the 1/8, 8's in the 1/4. But to do it the main cap where fretting and would fall off the block while freshing up. The decks where pulling up and trying to keep the heads on and cracking into the cylinder bores.

As stated an SHP or better block is worth the money and may be cheaper. Why put your money into the rotating assy and put into a $50 junkyard block.
 

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Discussion Starter #10
Because I am on ocean away and price structures are different here... I can get my old block done for $1000. (An old 400 will be $500 here)

Getting an SHP or better would be triple the cost of the U.S. base price.

I need to freshen up my 400 now that it is out... saving nickels and dines would take another 2-3 years. Since it's my daily driver... in needs to be up and running in a months or so.
 

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Add some steel cap with studs.
Short fill the block.
Add stud to the deck to try and prevent the deck from crack and pulling.
Go with MLS head gaskets. Watch your tune, read your spark plugs and monitor you AF's.
Keeping good fuel in it and not knocking it with help it live.
 

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I understand your concern over price over seas, so my question is why do you want to run 12psi. You stated 95% street use and mostly driven like grandma so what is the difference between frying the tires at 8 PSI vs. frying the tires at 12 PSI? You are not going to hook up either combo on the street anyway so why push it and risk blowing it up? JMHO.
 

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Discussion Starter #13
Robert: thanks!!!

Greg: Indeed. EXCELLENT JMHO. Hmmm. Power is addictive I guess. I would like to feel more top end. Another point is, the rare times I get to track, I can't seem to run faster than 12.3x. This should bring me down to high 11s for sure. Just a personal goal.
 

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I just re-read your post and it says the whole short block is stock. Does that mean factory crank, 5.565" rods and cast pistons? If so, no way would I step up the boost. Also, I'd say look over the whole combo....expecially the chassis and drive line. 460 HP to the tires tells me you are making plenty of power to run well into the 10's so grunt may not be the issue. What was your 60' time? MPH?

Tell us about your converter, gearing, suspension, etc.

8 PSI can get you into the 9's if the rest of the combo is well sorted out.
 

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Discussion Starter #15
Ahem. Yes. That was a stock 400 rotating assy - short rods and all. I will replace it with forged everything and 6-inch rods likely. For sure new assy.

My 60-foot sux. 2.1 at best.

The car is a 1973 Chevelle. 4000 lbs. The rear is 3.42:1 with a lock right locker on 325/50R15 BFG drag radials. Polyurethane all over. Boxed lower arms in rear. 50/50 shocks and stock coils. Front shocks are adjustable and coils are PST ground zero minus a coil.

Brace yourself! I am running a 200-4R. I rebuilt it myself with all hardened parts. The converter is a D5. Stall 2400? I like being different... And OD. ;)
 

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Sorry but I can't make the numbers add up....any chance that 460 HP was at the crank on an engine dyno? My buddy had a 70 Chevelle and he ran 12.0s at 110 MPH with a naturally aspirated 406 putting maybe 350 HP to the wheels. My Camaro ran 11.23 at 118 natually aspirated with about 370 to the wheels. 460 to the wheels and a 12.3 at 100 don't add up.:confused:
 

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Discussion Starter #18
I'm sorry: 121mph!!! 12.29 sec

Its 460, at wheel. I have a very rough time hooking. Further, tracks are not prepped here
 

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this is off wallace racing web site. the numbers from above plus a earlyer statement at 4000 lbs.

Your HP computed from your vehicle ET is 383.30 rear wheel HP and 425.88 flywheel HP.
Your HP computed from your vehicle MPH is 510.73 rear wheel HP and 567.48 flywheel HP.
 
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