teksid shortblock as an option?

[usaf_branham]

ive been debating about what im going to do...

i dont know a whole lot about the teksid block... i get that its about 70 lbs lighter because its aluminum, and apparently it can hold about 1000 rwhp.

now...

im looking at options to go with a forged bottom end. i am mechanically inclined enough to build a short block myself. i have a kenne bell, and i want to run 15+ psi (and eventually spray it).

this leaves me a couple of options. i was originally going to go with a forged stroker frpp boss block from MMR, low compression pistons, and top it off with the 44cc twisted wedge heads w/ PD Supercharger cams specifically for trickflow heads.

however, i just noticed there are 2 teksid's for sale on craigslist in my area... one is from a 98 cobra and comes with the forged cobra crank for 500. the other is a long block from a mark VIII for 300.

does the mark VIII motor have a forged crank like the cobra?

the cobra motor had a bad rod bearing, so i know that either way the cookie crumbles, im looking at machine work... so how much can the teksid block be bored out? i am guessing that because its aluminum, its sleeved... can that be machined, or would it need to be re-sleeved?

i am assuming that if i bought the cobra motor and the crank is salvageable, and if i put a nice set of forged h-beam rods and forged pistons w/ clevite bearings i would be in it around 2500 w/ machine shop... it should be good for at least 1000 rwhp... am i right?

Also, im thinking that a KB 2.1 spinning 15+ psi (small sc pulley & larger crank pulley) on a forged 4.6l w/ trickflow heads and cams should net me between 550 & 600 rwhp. does that sound correct? or am i completely off?

Sorry for the long post, and please dont rip me up if im completely off, im just trying to get my stuff in line before i go dropping cash.

Thanks!

 

[N8Dogg98]

The Mark VIII doesn't have a forged crank, but I don't think you need one unless you're going to be spinning the engine past 7K rpm's and are planning on exceeding 600 RWHP (someone else should perhaps chime in on the durability of the cast crank).

Yes it is sleeved and I don't know how much room you have to bore it out. I think that book Sean Hyland wrote about the 4.6 says, but I don't remember what it was and it's packed away so I can't check for you.

I don't know how much your engine would be good for, perhaps someone else knows.

I think the 550-600 RWHP is a very reasonable estimate.

 

[JymboSlice]

Just find a nice used cobra teksid block on ebay that wasn't damaged.. thats what i did for like $300. You dont need to stroke or bore the motor out any, as that will give you little to no power. Get the block cleaned up, check the bore spacing and then get a rotating assembly. I honestly dont see a cast crank holding up to 15psi of boost and NOS on top of that.. you might as well get a forged crank, rods, and pistons (id stay around 9.0 C.R. for the KB). definently get the trick flow heads and a nice set of cams though.. Maybe you would even want to swap the 2.1 KB for a 2.6 or whatever. Then you probably wont need to run NOS and youll forsure be around 600rwhp.

 

[Dark04GT]

I agree with the above. Your 2.1KB is best at 14psi and below, yes it can run higher but it will start to lose efficiency and basically you will have a higher psi number but you are going to be making less power per psi. Your build is already pretty serious.... you should upgrade to the 2.6KB, it will live much better at those higher psi values.

From what I have read the cast crank is pretty solid but most things I have seen they recommend the forged crank when you go above 500rwhp. The teksid or the mark VIII sounds like a great idea. These 4.6's run for a long time, as long as you measure out and clean up the block you could potentially get some good savings by going with a mildly used block.

 

[Rick 91GT]

Grab the 98 Cobra crank, turn it as needed, good forged rods and pistons and youll hold 1000hp