Racer Brown ST-21

[fishy68]

Jim is a real nice fellow. I like how he doesn't try to treat you like you don't know anything like some of the other cam tech lines do. I just had him grind a small solid for my new 408 and it runs fantastic.

 

[Lakeeffect]

Took your advice Fishy. First time ever working on heads. light bowl work cleaning up the chambers like you said. Going to try it.

 

[fishy68]

Looks good but I'd also smooth the pads down next to the spark plug entry.

 

[Lakeeffect]

Yeah i just got a new bit for my Dremel to do that next. Hope fully my home porting wont hurt me . i tried to be conservative doing it.

 

[Illahe]

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.

My 340 with 2.02 10.5 and Isky Mega 280 was slow off the bottom, 4 speed; once it hit 4 grand 6700 came REAL fast! @.02 over rated, 1.88 are fine. I went to 308 casting heads 1.94 and a 245/245 510 solid over 11.5:1 real happy! Look up Myron on here he was running stock eliminator wit 1.88 and kicking ***!

 

[Mean416]

I think compression target guidelines are somewhat misleading. Saying this cam needs to have X compression or it won't work well, it doesn't tell the whole story.

No big cam is gonna be great down low. Poor idle quality and off idle response, low vacuum levels, etc. Having lower compression makes it worse.

In terms of power output, as long as you're in normal ranges I believe you're fine. If we could afford race fuel all the time we'd be running 14:1 compression but $30/gal isn't practical.

Compression will raise or lower the curve that the cam produces. Higher compression will give you more power. Great. But if your current engine "only" has 9:1, it'll still be fine and make good power. Just not as much. Good thing is pump gas should never be a problem though.

If you care enough, Richard holdener did a test specifically on this point, where he tested the same combo at several compression levels. Guess what the 8:1 big cammed motor still made good power. Not as much but the dyno curves proved the point.