3400 vs. 3500

[El_Diablo]

hey guys,

i know thers been tons of info thrown around and i was just going to go with a 3400 but im contemplating using the 3500 instead since thanks to CNCguy and Ben its a lot easier swap now

my project will be a malibu and i want to build the engine for boost



i think the 3500 offers more strengths if i could get a forged crank and i know the oil squirters would help for longevity and cold operation but the 3400 is proven strong... what are the weaknesses of the 3500?

i will be replacing the rods and pistons either way but which would be easier to work with when it comes to doing this? (in a product purchasing standpoint)

[Superdave]

the 3500 crank IS forged


From what i've seen the 3500's rods may be the weakest link. Everything else is top notch.

[Joseph Upson]

hey guys,

i know thers been tons of info thrown around and i was just going to go with a 3400 but im contemplating using the 3500 instead since thanks to CNCguy and Ben its a lot easier swap now

my project will be a malibu and i want to build the engine for boost



i think the 3500 offers more strengths if i could get a forged crank and i know the oil squirters would help for longevity and cold operation but the 3400 is proven strong... what are the weaknesses of the 3500?

i will be replacing the rods and pistons either way but which would be easier to work with when it comes to doing this? (in a product purchasing standpoint)

Even the cast crank in the 3500 is stronger than the 3400 crank by its intended purpose to help reduce engine noise by being more rigid from the larger crank pins. Since CNCguy is working on a VVT solution why not wait a while longer if you can and get the 3900 which has the oil squirters on all of the cylinders instead of the 3500 which only wets two. Since I can't be sure of the 3900s performance without the VVT and lockout that CNC is working on I hope and can't spare the expense now to get its cam reground, I have opted to stick with my 3500 and turbo grind cam install with the 6spd if all goes well.

After crunching the numbers on Desktop Dyno I show more than 400 hp and nearly as much torque with my cam and twin turbos plus a 28x10x3 intercooler and water/alky injection for added protection at just 10 psi using the 3500 head flow numbers as tested on the 3400 bore and over 450 hp at 15 psi. The engine is built for 87 octane at 9.8:1 compression so only the water injection or intercooler is needed for 10 psi detonation insurance, using both should make 15 psi very safe especially on 93 octane. I'm planning on tuning with the Zeitronics wideband outfit to make sure it gets a good tune.

I'll be posting pictures of it soon because it has to be completed soon before school starts.

[SappySE107]

3500 pistons and rods are going to be more difficult right now. Im not sure what you can do for pistons other than custom. The connecting rods may be the same as something else if you know any motors with 5.9" length rods. The connecting rods might be just fine though at those power levels. I think the reason we see bent rods is from hydrolock. Its way too early to tell though so unless someone wants to build a boosted stock bottom end 3500, we won't know. The stock 3400 bottom end is proven for 400+ hp (see boosted 3.4 DOHC engines) and I can only hope that GM didn't make them weaker with the new design.

[El_Diablo]

the 3500 crank IS forged


From what i've seen the 3500's rods may be the weakest link. Everything else is top notch.

only certain ones, hence my wording


the pistons will be custom either way to knock down compression for streetable boost but im wondering about journal sizes for rods

for me the easier solution for mounting and tuning is the 3500, hence my reasoning for narrowing it down to these two... also kinda hoping to make more than 400... but shhh, you didn't hear that

[farmerz24]

i thought eagle makes a 5.9 or 6.0 rod for a 4.3 sbc which has the 2.25 crank pins. may only be need to be narrowed but will work. since you are getting custom pistons offset the pin .1 inch higher in the piston to make the 6.0 rod work.

[SappySE107]

I think GM left it to 5.9 because of the piston pin location. Its clear up in the rings already.

[MidnightriderZ24]

i thought eagle makes a 5.9 or 6.0 rod for a 4.3 sbc which has the 2.25 crank pins. may only be need to be narrowed but will work. since you are getting custom pistons offset the pin .1 inch higher in the piston to make the 6.0 rod work.

this is my exact plan, custom pistons with 6.0 rods. having the piston pin .1'' higher should work.a stock 3400 bottom end is pretty damn stout if u ask me lol

[El_Diablo]

trying to get the top ring land .25 down from the top of the piston already though... hmm, duno how well that would work with a 6" rod and moving the pin up

[El_Diablo]

BUMP!! 3400 or 3500? which has more and build-ability and which should be able to handle boost better? also, same mount locations? (sorry, out of it today)

[MY91GT(Z)]

3400 Has The Similar Mounts That U Would Be Able To Use To Make The Swap Easier And I Would Think They Both Handle The Boost The Same And The 3400 Has Been Around Longer So Theyre More For It If Anything Goes And Ppl Know More Bout Them Than The 3500

[El_Diablo]

thing is im already looking at a top end and crank swap if i go with a 3400 and i would need rods and pistons anyways for my power/boost goals...

only thing is really the mounts and which block would hold the power and be easier to utilize given my plans

[MY91GT(Z)]

what kind of car is it goin in and what yr cause theyre places where u can find poly mounts but either way i would say 3400 is ur better bet cause like ben said theirs not much out there for the 3500 just yet and they both r the comprimable to ea other its just easier to go w/ 3400 and not have to wait for as many custom parts as u would w/ 3500 and the 3400 can handle quite a bit of hp stock. ive heard that that the lower end on 3400 can handle around 400hp which would put u in the 11sor faster providin u have the suspension to handle that along with the driveshafts

[El_Diablo]

98 malibu...

so basically right now im thinking 3500 top end setup P&Ped for boost from Ben once it becomes an option and a 3500 forged crank swapped into a 3400 block with custom pistons and rods

hows that sound? and how much work is it to swap in the 3500 crank? same journal sizes? i know i'll have to use the crank trigger from TCE but beyond that what mods should i be looking to do to get this to work?

[bszopi]

Main journals are the same size, but the rod journals are larger. Therefore, you would need custom rods to fit the larger journal. You will also need to clearance the block and oil pan for the increased swing of the larger rods. If you are planning on a crank swap and a 3500 top end, you might as well just go with a 3500 so you don't have to worry about making sure the block and pan are clearanced properly. You will also gain the oil squirter on 1 set of cylinders. And, you'd probably be able to pick up the entire engine for about the same price as trying to piece the other pieces together.