Old School SBC Help!

[pretentious_pontiac]

It's tough to tell with the pan down IMO.

Personally, I'd not worry about it and run it until it doesn't lol. But if you want to know what it is, off with a head and start measuring stroke and bore. But what is the point really? If it runs properly, then leave it alone.

I'll throw this out there for the Anti LS Consortium, a properly built SBC either as a 355 or 383 if properly tuned will stomp most any LS. It takes some motor building effort to make 400-450hp, but it's not even remotely impossible. But it will take a good head and cam setup - and of course a tune. The nice part (cheaper than LS) is that it will drop right in without oil pan, motor mount issues, etc. And if you want more, then a turbo goes onto a SBC just the same as it goes onto an LS. Been there and done that - trust me - it works.

If you want a good read about going fast with a SBC, then find Ole Bob's 9C1 thread - a 355 that hauled some serious *ss and looked good doing it.

Really my main reason for wanting to know is because I do some casual racing and run 100 shot of nitrous. So far I've been 12.82 at 107 which for me is a fun number. I was just wondering exactly what engine it is so I can figure out how far I can push it without oiling down the track too soon.

 

[pretentious_pontiac]

just for the halibut😆 see if there's more than 3 freeze plugs per side.if there's three per side you've got a 4 bolt 400.if there's an outline for a second one in the middle of the block yet there's only two actual plugs per side it's a 2 bolt 400.

I will look for sure. I wouldn't be mad at that either lol.

 

[64nailhead]

Really my main reason for wanting to know is because I do some casual racing and run 100 shot of nitrous. So far I've been 12.82 at 107 which for me is a fun number. I was just wondering exactly what engine it is so I can figure out how far I can push it without oiling down the track too soon.

Nitrous doesn't care about engine size. Keep adding it while watching the plugs and fuel pressure. As long as both of them are happy, then you'll be fine.

If it's a cast piston deal, then look hard at the porcelains to see if they are gaining aluminum specs - that's not good hehe.

 

[ELCAM]

As far as nitrous goes keep in mind a few things.

The 2 bolt main cast crank 11/32 rod bolt standard rods with pressed in pins and cast pistons never made more than 300HP and were redlined at about 5200 RPM in a factory build.

The 4 bolt forged crank 3/8 bolt rods with better pistons were rated at a max 370 HP though I think that was underrated 400 HP being more accurate. This set up red lined at 6000 to 6200 RPM (higher on the shorter stroke 302 and 327) in a factory build.


Of course hot rodders have been getting better numbers than GM did with many tricks and improvements.

Such as: Chamfered oil holes, cross drilled oil passages, main bearing studs, higher volume and higher pressure oil pumps, modified oil pumps to reduce pulsing, better harmonic dampers, hypereutectic or forged pistons, better piston rings, windage trays higher tensile strength rod bolts and of course all new valve train.

SB 400 never came with forged cranks they were lower RPM torque engines and were very heavy duty, you lost some of that heavy duty turning down the bearings to fit the 350 block and rods.

The stroked 383 using factory rod bolts had to have one outside edge of the bolt head ground down for cam clearance these usually lasted 50,000 miles or more but you could see the bolt head failing somewhere above that number. (That number will be lower pushing it with nitrous.)

If you ever tear it down measure the main caps to see if they are egg shaped (the top to bottom longer than side to side this will tell you the caps were being over stressed and needed studs or aftermarket parts preferably 4 bolt splayed forged steel caps with the 2 straight bolts using studs. Same can be done with the rod big end the only cure is aftermarket rods.

Studs on the main caps are good for about 50 more HP and 300 More RPMs on a 2 bolt, 100+ HP and 500+ RPMs on a four bolt.

If you really want to gauge how far you can push it with nitrous you need to tear it down and see what was really done to strengthen it up and look for signs of over stress from what you are running now.

All numbers are off the top of my head and may not be 100% accurate, but they illustrate the idea.

 

[Supercharged111]

It's tough to tell with the pan down IMO.

Personally, I'd not worry about it and run it until it doesn't lol. But if you want to know what it is, off with a head and start measuring stroke and bore. But what is the point really? If it runs properly, then leave it alone.

I'll throw this out there for the Anti LS Consortium, a properly built SBC either as a 355 or 383 if properly tuned will stomp most any LS. It takes some motor building effort to make 400-450hp, but it's not even remotely impossible. But it will take a good head and cam setup - and of course a tune. The nice part (cheaper than LS) is that it will drop right in without oil pan, motor mount issues, etc. And if you want more, then a turbo goes onto a SBC just the same as it goes onto an LS. Been there and done that - trust me - it works.

If you want a good read about going fast with a SBC, then find Ole Bob's 9C1 thread - a 355 that hauled some serious *ss and looked good doing it.

I love my small blocks, but I'll put my LS6 up against a 350 without hesitation. It's going to take money and effort to outrun it. With only longtubes it should be around 430 at the crank based on what others Dyno. Seems to be 25+ whp gains there. If I ever get off my *ss and shove the cam in should be 420whp whatever that translates into, 465ish? I deal more in whp as that's what folks post up and nobody really cares about crank HP with the rest of the car being such a huge variable. WHP and trap speeds tell you all you need to know.

 

[pretentious_pontiac]

Would just throwing a supercharger on top be easier on things? like running 5 or 10 psi on a roots style? I feel fairly safe running the nitrous now but I know it can turn catastrophic real quick.

 

[ELCAM]

A supercharger would increase pressure and temperature 100% of the time requiring an even more robust build, Nitrous just a few % of the time. A turbo is somewhere in the middle.

 

[pretentious_pontiac]

Guess its just perfect where I am lol I'll run this setup for a while and when it goes I'll switch to something more robust. I am racing in Sick Week Florida next year so who knows that might be the end for it.

 

[Supercharged111]

A supercharger would increase pressure and temperature 100% of the time requiring an even more robust build, Nitrous just a few % of the time. A turbo is somewhere in the middle.

I slapped a blower on my then 225k Vortec. A mild blower doesn't require anything more than a lack of ignorance with the tune. It's not going to turn a turd into a fire breather.

 

[64nailhead]

Guess its just perfect where I am lol I'll run this setup for a while and when it goes I'll switch to something more robust. I am racing in Sick Week Florida next year so who knows that might be the end for it.

I’ll be watching if I can find the live feed. I’m envious of you though, I wanted to run in it, but FL is too much of a hike for me.

Regarding the power adders, you’re using the easiest and most reliable one presently. More HP is only a jet change away.

Good luck to you!!