TEST RUNS on BLown SBC

how much boost can a stock chevy small block take? well
I went to a rent day at the track yesterday made 21 runs on the old 283 chevy block punched to 300ci fully filled, splayed caps with my 1471 just to see what will happen, since so many people said it won't pass the burnout box with that block.
I wanted to see for myself if that was true. It did make it out of the burnout box. I started with 20 psi boost then went up to 24 psi boost then made it up to 28 psi boost. I would have went up with more boost but did not have the pulleys to keep on trying more boost. I took the motor apart today and everything looked Okay. I did not find any kind of walking, I didn't find anything wrong at all. I don't know how much more boost that motor would take but I got 10 full passes with 28 psi boost. 5 and 6 with 20 and 24 psi boost. I was really looking to brake that motor to see how much I can push it, but it never happened. I will put in my 400ci motor now. Just thought I would share this information with you all. Anyone out there ever tried this much boost with a Stock filled splayed caps chevy small block before? I would have loved to try 32 psi boost or 36 psi boost to see how much it would take before braking, guess not. I was expecting it to brake after 20 or 24 psi boost. but it held up like a champ!!!

 

1/8 mile or 1/4 mile? what was the 60 foots, also et and mph

 

good job not breaking your stuff.
20 -24 lbs is a great zone....... to the big end.

 

Car weight, rear end ratio, tyre hight and width, engine compression and ignition timing?

 

Why would you want to break the block when so many collectors are willing to pay good money for one?

 

1/4 mile runs, 1.18 60 foot, car weight 2600 lbs. rear gears 4.10, 33X10.5W TIRE. COMPRESSION 12.00:1, TIMING FROM 28 -26 DEGREE

 

I had posted about running high boost using a stock, filled with spalyed caps engine and everyone said it wont hold up, it wont work, I won't pass the burnout box, so I wanted to test and see how much a stock chevy block would take before breaking. I have to run low 7's high 6's with a weight of 2800 lbs. on 33x10.5W tires and want to know how much boost I can run without breaking, I wouldn't want to break in an event, so I took the chance on a rent day to see how much I can push the motor, now I know you can run at least 28 psi boost without breaking a stock filled with splayed caps chevy block. they said 28 psi boost was extreme that it would break in the burnout box. My testing can help me and others that wont take the chance to blow there stock filled chevy blocks to know how much a stock block can take.

 

How in the world did you make 21 runs in one day. not saying that you did not do it just wondering how


Lanny

 

Lanny,

I feel our "legs being pulled".....thats an average of 2 passes per hour

Jimmy, I'm from NY, what track were you at?

Keith

 

Jim,
Remember boost is the measure of resistance, what heads do you have? If you're using a stock style or basic port head you're gonna have high boost, that doesn't mean it's getting into the cylinders well. I ran 20 lbs of boost in my car and turned the blower up 13%, had the heads ported, and ran the same amount of boost as before. In some cases inefficiency will cause high numbers on a boost scale.

Josh

 

We rent the track like 3-4 times per year from 9:00am to 4:30pm
we pay $1,500 for 10 cars

 

Brodix heads

 

I didn't check the blower, head gaskets, just checked the bottom end, some time next week I'll take everything apart to see what I find.

 

Jimmy,

What track was it at, just curious?

WOW 7.5 hours, 21 passes thats almost THREE passes per hour. My block would have melted, alky or no alky....phew.

Keith

 

Atco, I was running to try and break just to see how much a stock block would take, how much boost do you run on your motor?

 

Jimmy,
We run 22 pounds with a Littlefield Retro 671 on a 477 KB Olbs combo. Right now we're at 32% over and everything looks great. We ran (last year) a 360 iron SBC with an unstripped 871 at 7 % UNDER (had 20 psi on the gauge, was more like 15 pounds).
We ran out of the box Dart Pro 1 215 aluminum heads and stock studded 2 bolt mains. The engine was NOT o-ringed and after a season (30 passes for us of match racing) at 36 degrees timing the FelPro head gaskets gave up and torched the heads. Upon dis-assemble and inspection the caps were beginning to walk but everything else looked great. We ran 7.70's in a 2100# car.
We now run 7.20's with our KB Olds set up, with only 30 degrees timing. We hope to hop it up and get into the 6's next season with just tuning mods (and maybe a little more boost )

You put more passes on your ride in one day than I did all this season...outstanding!! Keep 'er shiny side up!

Keith

 

I used 25T- 30-31-32T I just went by the pulleys for how much boost I ran
25-30 then went with 25-31 then 25-32

 

if you want call mike brothern at brodix he is one of the owners there and ask him if I had success with the whole small block thing i ran the brodix alum. block 400 bore winberg crank bme rods and pistons with a 10-71 hy helix, port nozzles all rcd stuff...what I am trying to say is IT WAS BLOWN UP MORE THAN IT WAS RUNNING...DO a leak down on it that will tell you more than anything..I got tired of putting sleeves in my wifes deep freeze to put in my block..that has been years ago now more wiser and now run a HEMI. LOVE TO E-MAIL YOU PICS OF A BRODIX HEAD THAT i STILL OWN it is busted from one end to the other now it is a shop converastion peice..also remember that the 400 bores are thinner. I like mike one day and that blower needs new stripping in it!!!!

 

Those 400 sleeves couldn't be any thinner than a 283 (3 7/8) block bored out to 4" for 300..actually 301". I remember those days and built my first SBC in about 1959. Those 283 blocks bored out to 4" were a disaster most of the time. Cylinders were to thin and barreled in the middle.

Man! all those pass's in 7 1/2 hours and you checked the bottom end and changed all those pulley's. You must have had a T/F crew working for you.

Hope it works out for you........blessings.........Ron Clevenger.