ideas on a new intake please

[mo' parts]

im starting to work on an intake mani for an 8 valve.
ive cut one up here..(removed the whole stock plenum) and im curious as to what would be near "ideal" on runner length ect. im thinking of using a 4" alum. tube for the plenum, with the t.b. on the end. ill make my bend in i/c plumming.

so basically, what would be a good runner length?
is 4" large enough for a good plenum?
should i let the runners extend into the plenum slightly? (sort of a velocity stack) im working on a couple picts now so you'll have a better idea what im looking for.
any other thoughts, ideas would be appreciated.

[mo' parts]

this is all ive done so far.... ill probably do the cut-outs like i have scribbled on there for the heat to escape rather than cooking the intake, including the section between the runners. should the plenum extend past the the last runner a few inches? my hvac knowledge says i should... im trying to keep this cheap and simple(TM way, lol). it may be the first welding w/alum. ive done. also i have a lincoln welder that has the gas kit, what gas/mixture of gas should i be using?
thanks again

[shadow88]

It looks like you're doing almost the same thing I was doing last winter. I never measured my intake runner length, but mine were about 6-7 inches. My plenum was probably about 3.5 liters, but I wouldn't fuss that size too much.

I'd cut back the runner length back alot, but that also depends on the expected power range. Longer runners make more low end power but trade off upper end power. The opposite it true as well. Velocity stacks are for tuning runner length for a certain rpm. I think a nice blend into the plenum area will work just fine. It did for me.

Try to keep the factory rail in use, so watch the mounting bosses and where you build the plenum.

http://www.turbo-mopar.com/forums/showthread.php?t=3234

Here's mine. It worked very well for me. Feel free to ask any questions (aside from welding) I didn't do the aluminum welding.