Racer Brown ST-21

[Lakeeffect]

Budget 340 build. ( dads old parts/some new)
I have a ST21 solid that my dad ran in his old back up 360 Dirt motor.
He thinks it would run great in my set up. I am just worried i could be killing my power out put with a cam i don't know much about.

according to 4seconds flat

ST-21
254
int
554
ext
520
22-26
10.5-13.0
4.10-4.88
3500-4500
They say 1.6 on the intake 1.5 exhaust. I only have 1.5 "273" rockers. will this hurt or help?

But after a search on here i came up with these specs
A Eng. P3412016 ST21-108 286 .520" 110 .018 .022 http://www.forabodiesonly.com/mopar/showthread.php?t=83966&highlight=ST21

Vehicle
Valiant-3100lbs Think Green Brick but with a few better suspension parts
3.90s-225-50-15's
TKO600 road race Over drive/alum flywheel/shaft
69 340 .30 over
Eagle SIRs
KB243's
LD340
70's 360 Smog heads with 1.88 intake fresh (long story, got ripped off. was told they had 2.02's and bowl port. would love an opinion on them also. Ether have them worked or run them and save for Eddys)

I finally got my car to a point i could drive it and did a few AutoX's this summer, But ended up dropping a valve in the 318. This car will see the street but i dont care about rough idle. Car will be seeing HPDE track days OFTEN.

Thanks Fabo.

 

[RustyRatRod]

What's the static compression ratio? that's a pretty gnarly cam. You're gonna need 10:1 or better.

 

[Lakeeffect]

What's the static compression ratio? that's a pretty gnarly cam. You're gonna need 10:1 or better.

I am not positive yet because i haven't decided if i will use the 360 heads and have not CC'ed them. I don't fully understand dynamic compression . How much would this cam bleed off compression? i want pump gas (93). But i am still considering E85.

 

[Lakeeffect]

But as i stated above is 286 duration or 254?! its about 12 years old. I know the real Racer Brown passed away and his right hand man took over. The Fabo link states it is from a old DC catalog. So the the cam could have been tweaked over the years? Maybe i should just call RB tomorrow.

 

[64physhy]

Looks like the specs say 10.5 or better. 4.10 gears. You would probably be ok with the 3.91's.

286 is probably advertised duration, 254 is @.050

 

[Lakeeffect]

Looks like the specs say 10.5 or better. 4.10 gears. You would probably be ok with the 3.91's.

286 is probably advertised duration, 254 is @.050

Yea I seen that but could 10.5 static be ok for street? if this cam bleeds off compression? Thanks physhy. i thaught my 3.91's would work with the close ratio trans and smallish tires.

I'll buy a new cam if i have too but i would rather save the money for new heads or have the smogers ported.

 

[RustyRatRod]

10.5 would be minimum for that cam if it really has [email protected]. That's a bungload of duration and will bleed off an equal bungload amount of cylinder pressure. But you should verify those specs. It looks like you're getting different specs from two different sources.

...and dynamic compression is also referred to as "running" compression. That simply means the compression ratio with the camshaft in consideration. Static compression is the compression ratio disregarding the camshaft. If you go to United Engine's web site, they have some nice calculators that'll keep you busy a while figurin all that out.

 

[64physhy]

It's on a 110 LSA, so shouldn't bleed down much, but I wouldn't go lower than about 10.2 because I like to get as close to the recommendations as possible to get the best out of it. It's going to take some work to even get 10.1 if you are staying with those heads. I'd keep the cam, and get the heads to match. Is that cam mech or hyd? Mine is hyd with a profile very close to that one making the power in my sig.

 

[Lakeeffect]

10.5 would be minimum for that cam if it really has [email protected]. That's a bungload of duration and will bleed off an equal bungload amount of cylinder pressure. But you should verify those specs. It looks like you're getting different specs from two different sources.

...and dynamic compression is also referred to as "running" compression. That simply means the compression ratio with the camshaft in consideration. Static compression is the compression ratio disregarding the camshaft. If you go to United Engine's web site, they have some nice calculators that'll keep you busy a while figurin all that out.

I have checked that out before but what does "Intake Closing Point (degrees)ABDC @ 0.050 lift plus 15 degrees" mean? 15 degrees initial timing?

I have read a lot on here in that last few weeks about guys with 10- 10.5 static compression having problems with pump gas. i know the fuel is only getting worse. but what is streetable dynamic compression?

 

[Lakeeffect]

It's on a 110 LSA, so shouldn't bleed down much, but I wouldn't go lower than about 10.2 because I like to get as close to the recommendations as possible to get the best out of it. It's going to take some work to even get 10.1 if you are staying with those heads. I'd keep the cam, and get the heads to match. Is that cam mech or hyd? Mine is hyd with a profile very close to that one making the power in my sig.

It's Mechanical. WISH i had the money to stroke it like yours 500 sounds too fun I am aiming for 400 but am starting to think its a bit out of reach. Well the pistons are flat tops and should come out .018 stock.. i havnt got the short block together yet. But the block has been decked .05 i think and the heads .10 I am at school and my paper work is at home. This is my first build so i could be confusing decimal points.

 

[64physhy]

You'll hit 400 no problem with some good heads. I think I saw some RHS heads for sale in the classifieds.

 

[IQ52]

But as i stated above is 286 duration or 254?! its about 12 years old. I know the real Racer Brown passed away and his right hand man took over. The Fabo link states it is from a old DC catalog. So the the cam could have been tweaked over the years? Maybe i should just call RB tomorrow.

Well, wouldn't you know it. I have Racer Brown cam cards for the SS-12, SS-23, EH-8, STX-22-105, X-107, 123-R-105, SS-H-9, SS-H-25, ST-12, ST-14, ST-15, ST-20, BUT NO ST-21.

I can tell you this though, the ST-21 is 286/286 degrees @ .017" lift and .520/.520 lift @ 1.5 rocker arm ratio. Racer Brown used .017" as the measurement for the advertised duration on all the ST series. Racer Brown wasn't shy about accelerating the lifter. So, it is most likely, 254 degrees @ .050".

His 1979 catalog lists cams in four catagories; street, street/strip, track and competition. The ST-21 is listed under "track".

I'd run that sucker, it should fly! I ran the ST-12 294/294 advertised and .485/.485 lift in a 1971 340 Challenger and it was a rocket. With 3.55 gears and G60-15 tires, it wouldn't even think about hooking up if I launched it over 1000 rpm.

 

[fishy68]

I have checked that out before but what does "Intake Closing Point (degrees)ABDC @ 0.050 lift plus 15 degrees" mean? 15 degrees initial timing?

I have read a lot on here in that last few weeks about guys with 10- 10.5 static compression having problems with pump gas. i know the fuel is only getting worse. but what is streetable dynamic compression?

That's the figure the program uses to determine dynamic compression. It's the intake valve closing point plus 15 degrees. Nothing to do with ignition timing. I don't know what the closing point is on the ST-21 but my ST-14 is 43 degrees so for me to figure it I'd add 15 to 43 (58) and that's the closing point to use in the calculator.

It all depends on how you build things. I just got my new 408 built and installed and it's 10:07 to 1 and with 33 degrees total timing it runs great on 89 octane. The heads I used are closed chambered EQ's and I had the block zero decked and used a .039 gasket so the quench works good. I also polished the chambers which helps to reduce spark knock.

As for your cam, I think it'll work fine if you get some decent heads. You have 2 options on heads

1. Spend a ton of money rebuilding yours and having big valves installed and have them ported or

2. you could buy a set of RHS heads with 2.02's and minor bowl work that will at least equal yours in performance and have new heads in the process. Plus they'd probably cost less than it would cost you to do your smogger's.

 

[IQ52]

Hey fishy68,

My old ST-14 timing card from 1965 lists the advertised duration at 266 degrees @ .017 and .485 lift. It shows real tight lash of .008" intake and .010" exhaust. Is all that the same as yours?

 

[Lakeeffect]

I'd run that sucker, it should fly! I ran the ST-12 294/294 advertised and .485/.485 lift in a 1971 340 Challenger and it was a rocket. With 3.55 gears and G60-15 tires, it wouldn't even think about hooking up if I launched it over 1000 rpm.

That made me Stoked. I will definitely be running it. Plus i like the sound. Thanks IQ52.

2. you could buy a set of RHS heads with 2.02's and minor bowl work that will at least equal yours in performance and have new heads in the process. Plus they'd probably cost less than it would cost you to do your smogger's.

I know i the Eddy's are more and not really as good with lots of problems out of the box. But 50'lbs is worth a lot to me. My dad offered/has a set of older W2's T&D rockers Ti retainers and as cast. I could use but they are closed chamber but i don't believe i could get my compression ratio down with out buying new pistons again.

Fishy68 you explained that really well. Thanks!

 

[Badart]

That valiant looks like it would be a lot of fun. Nice car.

 

[64physhy]

If the W2 heads are the 65cc version, your compression ratio with a .039 head gasket would be 10.9 (that's if your pistons really will stick out .018 ). .045 gaskets will get you to 10.7. .050 gaskets will get 10.5. If they are the 55cc heads, you'll be in the 12's for CR. If your dad offered you W2 heads with T&D rockers, TAKE THEM! Those rockers run around $800- $1200 alone, depending on which ones. If you cut bigger valve reliefs in the pistons, that will drop the CR a small amount more. I say get the W2's, run the cam you have with a .045 head gasket, and have a bad-*** car putting out way more than 400 HP.

I just re-read and noticed the W2's are closed chamber. That means they are probably smaller than 65, so your CR will be high. You'd still be better off going with some RHS or Eddy's than putting the money into the smog heads, IMO.

 

[fishy68]

Hey fishy68,

My old ST-14 timing card from 1965 lists the advertised duration at 266 degrees @ .017 and .485 lift. It shows real tight lash of .008" intake and .010" exhaust. Is all that the same as yours?

That's it except he says the lash on mine should be .017 int. and .019 Ex cold. He told me I could run it a little tighter if I wanted but not less than .012/.014

 

[fishy68]

That made me Stoked. I will definitely be running it. Plus i like the sound. Thanks IQ52.

I know i the Eddy's are more and not really as good with lots of problems out of the box. But 50'lbs is worth a lot to me. My dad offered/has a set of older W2's T&D rockers Ti retainers and as cast. I could use but they are closed chamber but i don't believe i could get my compression ratio down with out buying new pistons again.

Fishy68 you explained that really well. Thanks!

Your welcome. Yes the 55 lb savings is nice if you can swing them financially. Nevertheless I agree with 64Physhy to run the W2's even if they are heavier iron and the compression might be a little high. I'd at least cc a chamber to see how many cc's they are then you could figure what to run for a head gasket thickness that will get you down to 10.5 to 1 which I think it'd run ok on pump gas with that big of a cam. Also as I mentioned earlier polishing the chambers helps a lot on reducing detonation. I bet it'd be 450+ hp with that combo. and run on 93 octane if tuned right.

 

[Cudafever]

Pardon my ignorance, as i know nothing about cirkel track racing but.........
What RPM were you coming out of the corners at?
what was the max rpm you were turning?

we are assuming that these W2 are iron....or are they alu???
If is more of a race car then street car,(80/20) shoot for 11- to 12:1 and run Racing Fuel! Us the 21 cam and just retard the ign timeing and run 91/93 when your playing on the street.

Now if this is 75% street, well then you would HATE my sugestion above:mrgreen:

 

[Lakeeffect]

Your welcome. Yes the 55 lb savings is nice if you can swing them financially. Nevertheless I agree with 64Physhy to run the W2's even if they are heavier iron and the compression might be a little high. I'd at least cc a chamber to see how many cc's they are then you could figure what to run for a head gasket thickness that will get you down to 10.5 to 1 which I think it'd run ok on pump gas with that big of a cam. Also as I mentioned earlier polishing the chambers helps a lot on reducing detonation. I bet it'd be 450+ hp with that combo. and run on 93 octane if tuned right.

I like the polishing the chambers Idea. Better combustion + less detonation?
plus this would add a few CC's possibly? I may be going home next weekend (5 hr drive) i'll get the W2's and attempt to cc them. Anyone ever tried the Summit CCing kit? I don't know if i can get the short block together over thanksgiving but i'll try. Once i know how much the pistons pop out and the CC of the W-2's ill decide.

Pardon my ignorance, as i know nothing about cirkel track racing but.........
What RPM were you coming out of the corners at?
what was the max rpm you were turning?

we are assuming that these W2 are iron....or are they alu???
If is more of a race car then street car,(80/20) shoot for 11- to 12:1 and run Racing Fuel! Us the 21 cam and just retard the ign timeing and run 91/93 when your playing on the street.

Now if this is 75% street, well then you would HATE my sugestion above:mrgreen:

The W2's are cast iron. They are older versions with out the extra webbing. I like this idea although The car is definitely would probably be the 75% not that im driving it every day but i do have to drive it a Hour away for Autox's and alittle over 2 hours to any Track.

Oh and i think he would turn 7-7500 cant recall and the old man is probably sleeping.

 

[Cudafever]

7500 rpm will almost require a W2 or better head.......and if you really plan on that kind of Rs......you might want to consider it a full race car and just trailer it there.

 

[racerkilla]

off topic but nice bassett wheels, I run them on my legend car and always thought of putting a set on my 73 cuda

 

[Lakeeffect]

That valiant looks like it would be a lot of fun. Nice car.

Thanks Badart, your lower rad support is on my long list of things to buy. It is very fun.

off topic but nice bassett wheels, I run them on my legend car and always thought of putting a set on my 73 cuda

I had these wheels picked out before i even got the car. Lite and different than what most people have. I just called them up and they made them with backspace i needed.



Well i talked to the old man about the W-2's, He has a couple sets and the As cast ones actually have a crack in the outer water jacket. they are fixable but he brought up the fact i would need booku dollar TTI's to run them. His other sets are 300+cfm big valve race heads. Compu-flow the guy who did my block has decent prices on porting i think i will call him Monday about doing the stage 2 port http://www.compu-flow.com/porting.htm how much would putting 2.02 valve help me? keeping the 1.88's and having them ported would raise my cfm plus port velocity?

 

[Lakeeffect]

Talked to "Racer Brown" today. Really cool guy. He gave me the specs.

286 advertised
254 @ .050
.520 1.5 rocker
.520 1.5 rocker
108 centerline
Lash
.016 intake
.018 exhaust

.017 intake with aluminum heads