mexicanknight

Hey guys, ive got this idea floating around in my head for some days now.

Could it be possible to put some 4 valve per cylinder heads on a 91 V6 block?

I know it sounds strange, but i go the idea from the 350 32 valve heads.

Any ideas are welcome.

Greetings from Mexico

mexicanknight

ok maybe i didn't explain it well (my english kind of sucks), any way what ime trying to say here is that if you could bolt on 24 valve heads from a newer 60° V6

Six_Shooter

iTrader: (2)

Not feasible. The blocks are very different between the OHV and OHC.

You would be far better off to use the DOHC block, and modify for the opposite side starter.

mexicanknight

thanks a lot six shooter, so know i got a new qestion.

Can I use genIII heads on a 3.1 block?, and wich ones could I use?

firstfirebird

iTrader: (3)

They will bolt on, but you need to do something for ignition since the distributor will no longer fit. 3500 heads are too big for the 3.1/2.8 bore (combustion chambers hang over), so 3400 heads are the largest you can go. Try to find 3100/3400 heads and intake set from a 2000 or later because of larger valves and ports.

Street Lethal

iTrader: (16)

Although I'm absolutely sure that it's possible for someone with the means to fabricate a set, it really wouldn't be worth it in the end though....

mexicanknight

So could i put some 99-06 grand am heads on my block?

Here I can get a set of them for about 200 bucks

firstfirebird

iTrader: (3)

You will need the entire top end, and put a crank trigger on it, there is no room to put a distributor in with the 3x00's. I'm solving this by using a 3.4 block that has a crank trigger. You will also have to use FWD pistons or your compression will be high. It's going to take some fabrication to get them to work with the older blocks.

I'm still in the building phase of the engine, check out the thread "What's a Hybrid?"...
https://www.thirdgen.org/forums/v6/4...ts-hybrid.html


EDIT : $200 is a lot for used heads. You can get remans for a little more. Check out ebay, I found a set of 3400 heads (look for 170 or 487 castings) for cheap.

mexicanknight

Thanks for the link, actually each head goes for like 80 bucks with some head job donde to them allready, i´m also looking for some FWD pistons, my biggest problem is the dizzy, i really dont want to change it to DIS, i was planing on making a custom Intake just to clear the dizzy.

P.S. I also want to use my stock block because i dont have to much funds, im surviving on a college budget and dont have a job right now

noahTHEpurdy

iTrader: (1)

12 valves > 24 valves. IMHO. Just like 16 valves > 32 valves. IMO.

mexicanknight

Come again?

noahTHEpurdy

iTrader: (1)

There's advantages and disadvantages to it both.

First, the advantages;
Four valve per cylinder heads offer more valve surface area then traditional two valve per cylinder heads which means more fuel and air in and out over the traditional two valve per cylinder heads.This means more high rpm horsepower over traditional two valve per cylinder heads. Part of this gain comes from the tumble caused by the two intake valves as the fuel and air mixtures hit each other, they tumble into the cylinder, instead of swirling. Tumbling of the mixture helps promote high rpm horsepower.

Now, the disadvantages;
Tumbling of the fuel mixture also promotes the loss of low end torque. Swirling of the mixture, as from two valve per cylinder heads, promotes low end torque, the best would be a combination of swirl and tumble. To really take advantage of the four valve per cylinder heads, you will need to be able to run the engine at very high rpms. This typically means that the bottom end has to be built up with stronger then stock parts. Loss of compression with stock pistons. One thing you can bet, four valves need bigger combustion chambers. Special pistons with high lift cams. Most pistons are designed for two valve per cylinder heads, so, the eyebrows in the pistons probably will not be correct, and to get compression back from the larger combustion chambers, domed pistons are likely to be needed, which creates another problem with valve contact with the piston, which means even higher costs to have the pistons specially made.

So, weighing the advantages and disadvantages of the four valve per cylinder heads, it's never really worth the cost. Ever. For our little V6's or for our big V8's.

mexicanknight

thanks a lot ill be ditching the 24 valve idea and going for a hybrid with custom intake

mexicanknight

On the custom intake i was thinking of something like this:



But with longer runners to each port, something like an old cross ram intake, like a bastard child of that intake with this one:


What type of power could it make??
I guess it's mostly low end torque, so is that good or bad?