3400 Modified or 3400 Hybrid

[asylummotorsports]

The TH-125 if built right can handle about anything a 3400 in most any incarnation can throw at it.

But you need a guy who knows what he is doing.

Jeff at Engineered Performance can help you with this as far as LSD's and gear ratio combinations are concerned. (He can be alittle hard to get ahold of, but be patient. It's worth it)

After that a good builder and the right converter is important.

If you need more info on this contact me at my e-mail (asylummotorsports@yahoo.ca) and I'll do my best to direct you in the right direction.



AND the stock ignition is MORE than adequate! It's one of the few things GM did VERY WELL!

[sanjay]

I'd go with the 3400/3500 hybrid and 65mm tb. Ben at WOT-TECH has run some simulations and a stock 3400 has like 176 crank hp, but a stock 3400 with stock 3500 heads and a 65 mm tb has around 213 crank hp. Thats a 37 crank hp increase.
Now if you have a stock 3400 with street ported 3500 top end (heads, lim, and uim) and 65mm tb, you should have around 238 hp at the crank while bumping the power range up 1000 rpm. How does that sond?

Am I the only person tha thinks that 238 Hp is a little optomistic on the stock cam?? I'm thinking 220 tops..

I'm building a similar setup but I'm using 3.4 RWD pistons and a 62mm TB for now and going to a 65 later if it will help. I wasn't going to port the heads or LIM because I don't think it will be help much on a stock cam but if it by porting the heads & LIM I get close to 250 HP I'm all for it. Can anyone actually confirm that porting will give a significant gain on with a stock cam??

[IsaacHayes]

3500 heads are pretty good from the factory. They have a lot of velocity, port it too much and that drops, and so does power. Bigger is not always better. You can clean them up and gasket match but be careful you can do more harm that good if you hog them out. I would port the 3500 upper to 3400 gaskets at least or 3500 gaskets and then port the lower to match and taper down for sure though. You want a funnel effect. LX5 65mm TB works great on the 3500 upper.