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Author Topic:   350 build up
Whitelightning
Dirt Maniac

Total posts: 102
posted October 09, 2002 10:24 PM
I have a 350 chevy that I race in a pure stock class. I seem to be under power compared to the other cars. I want to rebuild this off season. Heres what I have: gm stock 350 crate engine with 993 heads every thing in between is just like it was sent from gm. My rules are:
1.Engine must be strictly stock for make and model.
2.Engines allowed .060 for bore plus .010 wear.
3.Stock pistons only no forged replacements.
4.No clutch fans
5.Cam lift .400/.420 maximum. No tolerance. Stock Idle only
6.Piston desk height .20 minimum. 70cc heads minimum.
7.400 Chevrolet must have dish pistons.
8.No high perfomance equipment.
9.Stock distributor
10.Valvle lash .000
This car also as stock 4 barrel Q-jet and stock cast intake per rules. My question is does these gm engines normally have dish pistons and if so will flat tops make a big difference(What kind do I need?) Also I think the 993 heads are 76cc. Can the be machined down to my ruke of 70cc? What about the block can it be decked or is it worth it? Or is .20 stock height. Also given that junk cam rule should I leave it stock or change it. Basically what would you do to make some power under those rules ? Thanks in advance to anyone who replys.

rico 08
Dirt Freak

Total posts: 372
posted October 10, 2002 03:01 PM
flattops should give you 10-20 more ponies i would run them if you can they are relatively inexpensive(way under 100.00 for cast)i would run a holley instead of the quadrajet,as far as the heads you would probably have to angle mill them to get even close to 70cc and the intake would also have to be machined to match up it's probably not worth it with what you have just run a thin gasket that will bring it up half a point on compression..20 deck is probably close to stock you can machine for zero deck height but you won't see much gain in compression for the expense,but the cam is where you can make some ponies if you play you're cards right,i'd get a cam like the guy's run in the vacuum limited classes run(like me)they usually have short duration short overlap and wide lobe centers don't order a cam specificly for an oval track engine it will have narrow lobe centers and definitely not sound stock as this creates more overlap i would even have a special cam ground just for you're motor especially with the lift rule you have camcraft will help you and get you in the right direction good luck.

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 10, 2002 08:19 PM UIN: 54865418
from those rule i'm willing to bet your lack of horse power is do to a lack of cubic inches. the cheapest way to more power would be to sell that 350 and get a 400 with a decent set of heads on her. another option maybe the gear could have something to do with it when do you notice guys getting away coming off the corner or going in or down the straights?

Whitelightning
Dirt Maniac

Total posts: 102
posted October 10, 2002 10:12 PM
i would say that they basically pull me down the straits and I am on 1/2 mile track turbo 350 trans and 3.42 gear

ray14
Dirt Full Roller

Total posts: 67
posted October 10, 2002 11:15 PM
how many rpms u turning?

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 10, 2002 11:41 PM UIN: 54865418
and what are you running for a tire roll

Whitelightning
Dirt Maniac

Total posts: 102
posted October 11, 2002 03:51 AM
about 5000 rpm and im sorry whats tire roll

jhon hollomon
Dirt Maniac

Total posts: 181
posted October 11, 2002 09:47 AM
I think what he means is whats your tire runout or distance around the tire.

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 11, 2002 11:18 AM UIN: 54865418
yes thats what i ment your way under what you should turn for rpms can you run smaller tires on the rear?i'm having the same trouble guys pull me off the corners so i went with a different gear . i was runnming a 3.23 with a t-350 on a smaller 1/2 mile and run 80in tires 205/70/14's and turn 5500 most guys in my class are running 6000+ are running a final gear of 5.67-5.86 compared to my 4.90 with a 3.23. so i'm putting in a 5.77 and going to run 70/15's instead of 14's hoping it will help me out. in your case i would drop about 3-4 inches in tire roll or go to a 3.73 or 4.10 gear

eastsidemob
Dirt Full Roller

Total posts: 27
posted October 11, 2002 12:29 PM
2.02 valves make a diffrence.
heres what i would do put a hydraulic cam in it or put a good cam and internally balance it a buddy of mine had this and it sounded stock set and ran smooth but it had a midwest # 6 cam in it. it was fast finshed top four several times flat top pistons are the way to go dish are jumk. how do they check your pistons? buy some good pistons u can buy flat top pistons for 70.00 dollars from speedway. id bore it .30 over and this should make a diffrence your gear probaly isnt enough a stock turbo 350 isnt good if your gonna one get a stage 3 shift kit in it and a light converter a stock one wont do the job. if u can run a 9 inch ford do so a gear in the range of 540 - 586 fianl gear is the way to go . thats what i think

Eljojo
Dirt Freak

Total posts: 273
posted October 11, 2002 10:17 PM
I'm gonna throw in with racer 17j. Put yourself a set of rings and bearings in the 350 and wrap it up in plastic bags. There are still a bunch of 400 cid motors out there and you should be able to track one down for under $3/4 hundred. I's suggest a set of speedpro hypereutectics. I'd bend the rules a tad and slip them onto a set of remanufactured 5.7 rods.(350cid rods) Your local machine shop can mill the tops down to the point there is a slight dish in the piston...LOL
Rico nailed it on the cam! Get professional help on selecting a camshaft. Camcraft deals with Reds and they positivly know their stuff!
On the cyl heads I gotta say--have your machinist flat cut them as far as he feels like would be safe. I'd install a set of 1.6's in the exhaust side-tech might let you slide on that -let your conscience be your guide!
I don't know of anyone who makes a shim gasket for the 400-but I KNOW they're out there!
Give Tony at www.dirttrackthunder.com a yell..he's good to deal with and his prices are hard to beat!

Whitelightning
Dirt Maniac

Total posts: 102
posted October 12, 2002 12:43 AM
ok so lets say find a 400 small block right, will It be stronger stock than beefing up the 350 under those rules, or will I need to do modifacations to it to.

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 12, 2002 01:48 AM UIN: 54865418
in the long run it would be about the same if you spent a bunch of money doing all kinds of stuff to that 350 . but you could just as ez do that stuff with a 400 and have an even better motor. personally i think the gear change would fix 95% of your trouble but thats just me my motors are junkers that i put a rering kit and cam in but my car handles better than 95% of them out there so i can get by

Whitelightning
Dirt Maniac

Total posts: 102
posted October 13, 2002 02:51 AM
so what you think maybe a 3.73 . what I now is aturbo 350 run it in second gear with the 3.42. also what rpm do i want to run a basically stock motor(350 or 400)

Whitelightning
Dirt Maniac

Total posts: 102
posted October 13, 2002 03:13 AM
oh yes I run a dirt track that is 4/10 or 1/2 mile or so that what everyone says, my tire roll is usally aroun 84(225/70/15) will say a 235/60 be a lot of help

dirtdobber1234
Dirt Newbie

Total posts: 2
posted October 13, 2002 10:39 AM
I guess everybody has there own thing so if anybody wants my two since here it is. We run a metric car in the i-stock class and are alway's up front with this set up.
Motor: 406
Pistons: flat top 10:1
Cam: 550 int./550 exh.
Heads: 2.05 int./190 exh.
Everything else is stock, even the rear end.
Most metric car's came from the factory with 2.12-2.41 gear's. with the TH-350 alway's in 1st gear we run the 2.41 on the 1/4 tracks and the 2.12 on the big tracks like Lonestar speedway in Texas. We tach out about 6500 rpm's we never run the motor under 6000. And I just cant express enough how important the Head/Cam setup is. our motor w/2.02 head's become's a boat anchor. and if you haft to pull vaccum I sugest using Rhodes lifters, at idle they bleed down enough to make a wild camshaft pull alot of vaccum.

dirtdobber1234
Dirt Newbie

Total posts: 2
posted October 13, 2002 10:52 AM
and also, I agree with everybody else on the horsepower/cubic in. rule, there is just no substitute. unless you are restricted with a two barrel carb. when we run any hobby stock class we alway's run the big motor, but when we run the i-stock class we run the 328. with the restriction of the 2 barrel it just runs better. oh, the 328 motor is a 305/400.

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 13, 2002 11:20 AM UIN: 54865418
i would drop down to an 81in roll on the 1/2 and 79 on the 4/10 . my buddy runs a 3.42 and runs 81's and turns about 6200 thats plenty in you ask me another one of our cars has a 3.73 and he runs 82 on the 1/2 and 80's on the 4/10turns about the same. basicly you can have a motor that puts out 1000 hp but if you aren't turning it hard enough it's not gonna put out any more than a stock 305 thats geared right

Whitelightning
Dirt Maniac

Total posts: 102
posted October 13, 2002 10:42 PM
so basically I should be alright with my rear gear. just time to make some more power lol, thanks for the replies


rico 08
Dirt Freak

Total posts: 372
posted October 14, 2002 12:48 PM
SCRATCH MY ZERO DECK THING,WHAT WAS I THINKING?

Factory36
Dirt Roller

Total posts: 18
posted October 14, 2002 02:37 PM
quote:
Originally posted by Whitelightning:
so basically I should be alright with my rear gear. just time to make some more power lol, thanks for the replies


Just wanted to throw my 2 cents in here... While there is no substitute for power/cubic inches, one thing that people often mistake is that they are underpowered when in fact they have an ill handling car. A lot of the fast guys will beat you in the turns and becuase they have a higher exit speed, it appears that they are out motoring you down the straights. With that in mind I also remember that you stated that you are only turning 5000 so gearing is probably the first thing to look at...

Geffy95x
Dirt Maniac

Total posts: 122
posted October 14, 2002 04:14 PM
Yes a gearing change should help.

Whitelightning
Dirt Maniac

Total posts: 102
posted October 14, 2002 10:17 PM
what do i want to turn a stock 350 I assummed that anything over 5000 on stock engine would have bad effect on engine

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 14, 2002 11:10 PM UIN: 54865418
around 6000 and no more than 6500 you'll be just fine one thing i forgot to ask you is do you have after market modual and coil in your hei that might help you out to if you don't already have it

Whitelightning
Dirt Maniac

Total posts: 102
posted October 15, 2002 01:55 AM
its all stock coil and module , but rules say stock ignition but im sure I could get away with it I think, whats the advantage in the moduls. Thanks

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 16, 2002 10:39 PM UIN: 54865418
get a accell modual and a msn stock replacement coil take the stickers off and they will never know the difference . the stock stuff you have peaks at around 4500 so your not getting a good enough spark with that stock stuff to produce good upper rpm power

Whitelightning
Dirt Maniac

Total posts: 102
posted October 17, 2002 12:39 AM
cool , did you mean msd or msn

racer17j
Dirt Forum Champ
Total posts: 1565
posted October 18, 2002 12:37 AM UIN: 54865418
oops to many hours in the field this week ya i ment msd lol

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