Street strip use with an SB2.2?

[Troy Patterson]

You know, I am a fan of reverse pattern cams - the Crower numbers you posted would be very interesting indeed. The spring pressure though, yikes.

Troy Patterson TMPCarbs.net TMP Carbs

[68rs406]

I'm not familiar with the Pro Sys's HP950. Does this version run the 1 3/8" dia, venturi or does the HP950 represent the actual cfm? By my own standards, your 406 was under-carb'd. I'm running 1.60" - 1.172" venturi carbs on 351 well under what you are / will be running.

It's a pretty basic deal, it's based on a standard HP950, so 1 3/8 venturi. I believe the wet flow CFM was 850+/- if I recall. It worked very well on my 406, and I wondered about whether or not it would be undercarbed for the SB2.2 deal or not, the cubes are less but rpms and flow potential is far more. Do you think it would be a pretty bad choke point?

Thats an interesting design on that venturi, is it egg shaped down to round at the butterflies? What kind of flow potential would the 1.376 body on my carb have if it was reworked? Is it even feasable or would I be better off starting over if I went to another carb at some point?

I agree about the cam, not an optimum NA grind, it was designed for a turbo application so I assume thats why it has a short exhaust side. I thought it was not usable on a NA street/ strip deal specifically with a 114 LSA (again it will be likely less than 2000 miles a year on the street), but after talking to Crower and they said it would work I started questioning all I knew about cams in 23* motors compared to the SB2.2. I agree the spring pressure seems pretty high for street use, maybe I misheard the guy, but I'm pretty sure thats what he said. The cam I have for my 406 has 200# seat, 450# open with a 258/262 duration, .418 lobe on a 105 LSA, why would the SB2 cam be so different? The Sb2 cam is a standard core also.
I'd be curious what the cam guys think would work spring wise with what I'm doing, and if it was livable on the street.

You know, I am a fan of reverse pattern cams - the Crower numbers you posted would be very interesting indeed. The spring pressure though, yikes.

I know it, thats the one thing that really has me wondering on this SB2.2 deal, the spring pressure seems crazy high, and while I have no issue with having what most people think of as a radical street motor I don't want to have to rebuild the top end every year.

The deal with this motor though is I understand this is not an optimum package in some aspects (cam and compression specifically), but this is not a max effort race motor either. I just want to make this motor live on the street (occasionally), and in order to make a good deal stay a good deal, not have to change a whole bunch of parts right away, maybe down the road though when I want more, and I could make individual changes then. But I don't want it to be a complete mutt until a complete redo is performed though either. I just cant aford to buy this motor and have to start over to make it work.

What appeals to me is I can get this thing very reasonably, it allows a ton of room to grow, and they seem to make 600-700 horse pretty easily even with low compression like they ran in the Bush series (9:1 I believe?).
But if I have to start changing a whole bunch of parts, the up front cost won't really matter and the project could go through the roof (gee that never happens... )

I really feel like this can be done if keep it reasonable spring pressure wise, lean to the mild side on the build, etc., but these damn SB2's seem to be so different than what I'm used to, I feel like I'm 16 again building my first motor here.... It sucks.
I'm all ears for suggestions you guys, especially the SB2.2 guys, and thanks again for the ongoing opinions and replies, even if you tell me it's a waste of time and stay with my 23* stuff, if I ever see you at the track I owe you a cold beverage of choice!

[Troy Patterson]

It's a pretty basic deal, it's based on a standard HP950, so 1 3/8 venturi. I believe the wet flow CFM was 850+/- if I recall. It worked very well on my 406, and I wondered about whether or not it would be undercarbed for the SB2.2 deal or not, the cubes are less but rpms and flow potential is far more. Do you think it would be a pretty bad choke point?

Thats an interesting design on that venturi, is it egg shaped down to round at the butterflies? What kind of flow potential would the 1.376 body on my carb have if it was reworked? Is it even feasable or would I be better off starting over if I went to another carb at some point?

The 950 was a serious choke point on your 406 and it will be even more so with this motor - even with a wet flow rating of 850 cfm. Dyno results may or may not not show much of a difference between your carb and say a 1000 HP, but there would be a vast difference between how the two will drive, the 1000 HP having a good deal more throttle feel and response - therefore more fun, assuming the 1000 HP is calibrated reasonably well to the engine.

The 950 center section doesn't have enough wall thickness to make it large enough to warrant the effort. On the cheap, you could replace the center section in that carb and re-jet the metering blocks.

If the motor is complete or you can simply put that cam in it and have a little fun for a while, by all means. To offer the counter to that, it'd be a real shame to break something in the valve train and loose the engine on a romp.

Troy Patterson TMPCarbs.net TMP Carbs

[68rs406]

Thats interesting regarding the carb, I definitely don't doubt it either. Regardless of what direction I go here with this motor, buy the SB2 or just build a shortblock and run what I have, maybe I'll get in touch with you regarding my carb, heck you are right up the coast from me.

If the motor is complete or you can simply put that cam in it and have a little fun for a while, by all means. To offer the counter to that, it'd be a real shame to break something in the valve train and loose the engine on a romp.

Exactly my concern, I really can get a prett decent deal on the complete motor. The cam and springs are out of it currently, (it has a huge twin turbo cam in it right now) but he has them and they are both still new. Your right a pile of broken parts are definitely no fun. What do you guys think this thing is worth like it sits out of curiousity?

Every time I lean towards my 23* stuff I start thinking man, that SB2 would be wicked and I should be able to make it live. I just don't know. At this rate I'll still be thinking about it next year at this time..... Maybe I should just go with what I know, I should be able to make more than enough power with my top end parts and a 400 short block to put me well into the 10's which is my current goal, what worries me is my future goal.....

[jmarkaudio]

what worries me is my future goal.....

NEVER FAST ENOUGH!!! I built my small block dragster figuring to run Top Dragster, getting it into the 7.40 range (still in the works), the Divisional in Gainesville a couple weeks ago had a 6.97 BUMP!!!

[Troy Patterson]

Every time I lean towards my 23* stuff I start thinking man, that SB2 would be wicked and I should be able to make it live. I just don't know. At this rate I'll still be thinking about it next year at this time..... Maybe I should just go with what I know, I should be able to make more than enough power with my top end parts and a 400 short block to put me well into the 10's which is my current goal, what worries me is my future goal.....

I'd go for it. If you don't, you'll jusgt be kicking yourself in the butt every time you think about it. You only live once. Once, right?

Troy Patterson TMPCarbs.net TMP Carbs

[68rs406]

Haha, you guys sound like my buddies! All a bunch of racers of course...

I have to admit I agree, why not, and I think you are right I will be kicking myself if I dont, the "what if" will always suck.

The only reason I'm being a pansy about it is the cost if I have to change a bunch of stuff, and if I blow a bunch of cash and suck a valve into the motor at 8500 that won't be good. Of course as we all know that can happen with any peformance build. Plus I always tend to overthink stuff, I hate to do things twice to learn..

Regardless the route I take, I'll keep you guys updated, the SB2 build would make a good story to follow probably. Thanks a ton for the opinions and help, and by all means keep it coming!

[68rs406]

what worries me is my future goal.....

NEVER FAST ENOUGH!!! I built my small block dragster figuring to run Top Dragster, getting it into the 7.40 range (still in the works), the Divisional in Gainesville a couple weeks ago had a 6.97 BUMP!!!

Man no kidding! I feel your pain, we run outlaw 10.5, one year the fastest cars are running 7.30's, next year you have Bill Glidden going 6.60 like a bracket car! We qualified 7.40 last time we raced in Vegas (2 years ago) and baarely made the top 20....

[Wolfplace]

With regard to spring pressure
I said it in my other post & will say it here
First off I don't think 650 open is a big deal with quality lifters, do it all the time in BB's which impart about the same loading as you will have at the lifter & I have engines with a lot of miles on them that are still seemingly happy

This engine is going to want to RPM,, short stroke, big bore 350 with great heads,,,
So,,,, with lack of credible evidence to the contrary I would opt for more spring not less spring
Beating the crap out of the valvetrain from lack of control vs running some light weight pansy spring for some ill conceived gain in loading on the lifter is in my opinion foolhardy in a roller engine
Unless this thing has some really light well thought out parts I would stick with some spring.
Not being privy to a Spintron I prefer the brutish approach

[Warp Speed]

I personaly wouldn't run a reverse pattern cam in much of anything, especialy an SB2. They seem to like at least 15 degree split.
What block are you using (SB2 type/staggered lifters or standard)? What is the valve stem size and is the valvetrain (rockers and bars ect) the cup stuff it came with?

[68rs406]

The block is a conventional Little M, so it uses double offset lifters (have heard mixed reviews on these) but they are new and I believe Crower, but not positive. It has 3/8 pushrods.

The valves are small diameter stems, but I can't say 100% for sure what diameter without taking them apart. It's obvious they are small stem valves though. I've been told they are inconel, but again, not positive.

I don't know the history of the upper valvetrain parts, they do look run before but they are in great shape, possibly take off stuff though.

The cam core is standard SBC size, will the SB2.2 grinds cost any more than a custom cam for the same block of any head configuration? I have no idea of needs on valvetrain/cam of these motors, but the block is standard SBC stuff.

Basically it's a brand new motor with what appears to be a combination of take off parts for the heads/ valvetrain, and new parts that fit the conventional block. I don't know much more than that, I have reciepts for bottom end parts and my buddy knows the guy that built the motor originally.
It's was built 5 or so years ago though and never run, the guy got bored and went a different direction I guess. He seemed to buy quality parts, the heads have been looked over by our Cylinder head guy and they are solid. It was built as a 900-1000 horse twin 60mm turbo street strip motor so that's why the cam seems odd. I would only assume (that's all I can do right now) he used the appropriate parts for it, apparently he's a sharp guy (?)

The positive side of this is I can take the motor home and tear it apart and check it out, if it won't work I can give it back to my buddy. I just don't want to waste a bunch of time if it's unlikely this thing will work for me. I'm leaning towards doing it but just want to get all the info I can first.

Thanks again guys.

[68rs406]

Hi guys, just wanted to revive this post and let you know I decided to pull the trigger on the SB2.2, I'm going to go pick the motor up in a day or two and get rolling on it.
I ultimately decided I wanted to try something different and the SB2 is such a good platform why not go that route. Of corse now I need to relearn everything I know regarding smallblocks from my 23* head days....
Just wanted to let the guys that gave me input on this which way I went, thanks again for the input!

Now I need to select a camshaft for this thing... I'll start another camshaft thread I guess to add to all the others already on the site .

[Troy Patterson]

Sounds like congrats are in order this motor is an excellent platform, er, just wish it was a Ford

Troy Patterson TMPCarbs.net TMP Carbs

[68rs406]

Sounds like congrats are in order this motor is an excellent platform, er, just wish it was a Ford

Troy Patterson TMPCarbs.net TMP Carbs

Thanks Troy! Appreciate it, and all the input you've given. I'm pretty excited about it just because it's kind of a new experience, I'm a die hard small block guy and I figure this is pretty much the best package to work with on an NA smallblock, and tons of room to grow.
Looks like I may neeed to get in touch this summer, I have a feeling my current carb may need an upgrade..

And for the record I have a Ford too, a 5.0 Mustang I've had for 17 years, I'm an equal opportunity hottrodder

Thanks again!
Sean

[mdross1]

New to SpeedTalk hello everyone! Been a hobbiest drag racer for several decades,never into NASCA.Reason I'm visiting this forum is for some insight on the SB2 top ends.Have an AFR head,Victor Jr,406" dynoed 560hp in a Boss Hoss motorcycle.This motor is setup with Nos Controlled carb plate.Looking into the power these SB2 heads can generate has me wondering about getting this same motor set up to be streetable.Want to run on pump gas.No plans to push the motor much over 6500.10 or 11:1cr should be streetable.Hoping to get into the 750/800hp range. Want to get as much info as possible before I commit to buying into an SB2 topend.