Finally posting my 3400 build

[johnnymossville]

I have beening thinking and have decided that I'll go with 9.5:1 CR. When looking at it, the lower CR will be easier on the engine and the trans, plus it would be the best way for me to go since I'll be driving it regularly and won't be on the strip every Sunday. I should be recieving the 3500 UIM before the week is out and then I'll be able to get everything ported. Just remembered that I'll have to order a TB adapter when I order the TB from the store. Spending money for parts makes you spend more money for more parts.

[3400-95-Modified]

Why do you say that? Seems that with a proper build they would be fine...

Poor oiling system in comparison to other motors out there.

I also didnt think you could get 530 lift on LS6 springs... But maybe I'm wrong.

[PCGUY112887]

Built '660's aren't the most reliable things on the planet,

Why do you say that? Seems that with a proper build they would be fine...

[johnnymossville]

Does anybody know the actual combustion chamber CC for the 3500 heads? I have read something like 32.4cc, is this correct? And by the way Issac,in an earlier post you suggested that I use a 3500 UIM and said to look on car-part.com. Well I checked and I'll be getting a 3500 UIM in the next few days. I also forgot to mention one my first post that I am running the 55 lb. FPR from the 3400 engine.Thanks everybody.

[montess408]

ther is a guy here on this board somwhere that raced them but he is not around much nowadayz

[sharkey]

the shift correction kit they sell isnt worth the money. you could buy it throught a tranny shop for half the price jbp lists it for. there is no kit to make the 125 shift firmer, however shimming acumulators and changing springs in the valve body can improve it. check around online for info, im sure someone has built a race 125

[johnnymossville]

I have seen a shift kit listed at JBP for the T125 auto trans but I was wondering if anyone knew about any other shift kits out there?

[IsaacHayes]

That is a great build. Those 3500 "shorties" will flow great and are a good option for those that can't build headers. They will flow miles above the stupid log style GM uses. With a good tune that will be quite a nice street rod.

[barrok69]

I happen to have a 2.2 Cav torque converter lying in the shed and iam planning on a shift kit. when this trans goes or in the sprig I would like to put a LSD in it. I also have a '93 Lumina 3.1 (wifes car and clean), '93 Corsica 3.1 that I was going to sell but may keep for emergencies, and a '85 Chevy truck (gas mileage sucks). I say daily driver cause thats the goal (according to the wife) . So you really think that I can pull off 11.5:1 with some really tight tuning? I've seen your post and it seems like your getting the hang of tuning. Plus I'm sure that I can get a lot of help here.

i wouldn't bother with a 4cylinder torque converter unless you want a 3500 stall speed

heres some calculations.

the more torque you apply to it, the higher the stall rate is.

for example... going with the formula... which is more correct than anything.

My 3400 puts out 193 ft-lbs to the wheels. assuming 20% loss in transmission, that makes it ~230ft-lbs @ the crank.

My 3.1L V6 jbody stock converter has a K factor of 177

K = Stall speed/(torque)^0.5

so 177 = X / (230^0.5)
X = 177 * (15.165)
X = 2684rpm stall

So i don't really see the need to go to a bigger stall converter

using a k=237 converter from a 4 cylinder would achieve a stall speed of 3594rpm !!

for my turbo motor which should be putting out minimum 350 to the wheels using lets say 400ft-lbs at the crank for calculations...

X= 177 * (400^0.5)
X= 3540 stall speed...

I'm most likely going to be going to a lower K factor converter. If the car was going to be a track whore... then yeah sure 3500 stall would be great. For a daily driver though....city fuel economy will be horrible.

[johnnymossville]

I happen to have a 2.2 Cav torque converter lying in the shed and iam planning on a shift kit. when this trans goes or in the sprig I would like to put a LSD in it. I also have a '93 Lumina 3.1 (wifes car and clean), '93 Corsica 3.1 that I was going to sell but may keep for emergencies, and a '85 Chevy truck (gas mileage sucks). I say daily driver cause thats the goal (according to the wife) . So you really think that I can pull off 11.5:1 with some really tight tuning? I've seen your post and it seems like your getting the hang of tuning. Plus I'm sure that I can get a lot of help here.

[Superdave]

One suggestion, while you have the trans out, swap the torque converter out with one from a 2.2 Cavalier/Beretta. The higher stall will help you out with the larger cam ad higher idle that it'll need to run.


i'm running near 11:1 on 91 octaine, i doubt you'll have any problems with 11.5:1.


This is a combo that will absolutely need tuning, do understand (and i stress this) that TH125 won't last long under that kind of torque. you'll need to add in a trans cooler and you should also consider having a shift kit installed or having a total "performance" rebuild done on it.


Built '660's aren't the most reliable things on the planet, If this is your only car then i'd go a little smaller on the cam. Maybe around .510 lift with a little more duration.

[johnnymossville]

After much consulting with Superdave, Ben, and Brad, I'm ready to post my 3400 build. If anyone has any input that they want to give,all will be listened to and any help will be appreciated. I have:

'00 3400 short block

3500 heads/LS6 springs, 3500 LIM and a '00 3400 UIM that I am porting to match the GM#12594826 steel gasket set

#1161 grind cam (210/215 dur.-531/531 lift) from the 60*v6 store

65mm TB (buying it next week from the store)

3.4 DOHC fuel injectors

two front 3500 exh. manifolds opened up to 2" at the flange

Flowmaster 2" in/ 2.5 out Y- collector

Dynomax Super Converter 2.5" in.out

Hooker Aerochamber muffler 2.5" in/out

I have been thinking about raising the CR and am undeceided how I want to do this. I could mill the heads .020" and maybe reach 9.5:1 or I could put 3.4 iron head pistons in and end up around 11.5:1. The thing is this will be my daily driver and it must be dependable. I can run 92 or 93 octane gas but will it be enough to run 11.5 on the street everyday? (any opinions?) I would love the performance upgrade compared to 9.5 CR. All this will be put in my '93 Beretta with an auto trans. and I'll be running OBD1. Any opinions or help? I hope to make this car haul a** but i'm sure it wouldn't compare to Superdave's 3500Z.