I think ill be going with a nice set of ported converted -10s which are 23* and they flow more at every lift point than the best flowing ls1/6 that ive seen....

 

can someone please give me a dollar amount on how much it cost to convert the sbc heads to fit our lt1?

could those track1's that Matt87GTA be matched up to an lt4 intake?

 

properly it could with some welding

 

well damn......that makes it more attractive.

so you could get the track1's ported.....i looked up assembled track1s at $1300 or so.

would all the valvetrain stuff still work since its all 23*?

and slightly modify a ported lt4 intake to fit?

that should make some serious power right?

 

A few things.

You could have the Track 1's hand ported but there are so many good CNC ports for them that I don't know if that's worth it.

http://www.brodix.com/onlinecatalog/...page13-14.html
http://www.weldtech.com/graphics/BrodixTrack1Chevy.gif

Now since you can get them for a decent amount $1800(on super sale)-$2500(normally) there is your starting point. The problem is that these heads require $700 (at least) of stuff done to them for the full LT4 conversion. So it's $2,500 to $3,200 for heads then.

That's getting up there, basically you are not going to gain more over a set of WELL DONE AFR's. Seriously. We are working on a high end AFR setup that should fall right in the price range of those things. The concentration will be on the midlift flow over the peak numbers because that's what makes the power.

Secondly, the intake.

Converting a LT4 intake over to a SBC head is not easy. In fact you would have to convert the head over to the intake because there is no way you can get the bolts into the intake to work with teh SBC bolt pattern. So on that note, why use a crappy LT4 intake when the conversion over to the SBC is about done for you. It would save a good amount of work on the heads for one, and a ton of money in the intake manifold. (Normally it's $350 to convert the SBC intake over to the LT4, plus the price of the intake)

If it was me and you wanted to stick with the LT4 intake. Stay with AFR's. The problem is the big time flow numbers like 330cfm are not what you are after, your after the bad *** 260cfm .400 numbers. That's going to make you more TQ and HP than the 330cfm @ .700.

If you want to go thru the hassel of changing the heads over for a LT1 then make it simple and stick with a single plane intake or any other SBC intake. There is a ton of savings in doing it this way in just the conversion costs. (No $350 for the conversion over to the new bolt pattern, plus the heads don't need the bolt holes changed over either that along with filling up the coolant cross over is most of the work on the head conversion)

We are working right now on a single plane conversion for the LT1/4 heads that will work with EFI. This would be even cheaper and easier with a set of SBC heads, because you would not have to convert the heads over to the LT4 bolt pattern and block off the coolant crossover. This all starts to become cheaper once you get this far into it.

On that note, a 23 deg head is going to be in LS1 ported head territory in volume to keep up or beat it. 210-235cc runners. A 18 deg head is usually larger volume, but starting with a small casting would make it small enough to work.

Bret

 

damn bret......youre like a walking book of knowledge

 

Not really I just think about this stuff all day.

 

BUH!

 

i do too, instead of doing my actual job

i need to switch professions.

 

Obviously mine is not an LT1 (ref. screenname and sig) and I don't have much experience with LT1 specific engine stuff. That being said, couldn't you use the standard SBC heads (Track 1s for instance) with a crossover pipe setup grafted onto it (can't be much, maybe $200) with something like a Miniram that is made for standard SBC heads and skip all that customization? If you did a Miniram you could end up with a better intake while you are at it (marginally better than an LT1 intake, but still better nonetheless)....

I don't know what the measurements of the LT4 intake ports are, but I was under the impression that it is a tall port intake and thus a 1206 sized port would be about the same requiring just a little porting on the LT4 intake to make it work.... If welding is required the price tag gets a bit worse and running my above suggestion might be better - more expensive, but better.

 

Bret, what if you end up with both?

http://www.rx7club.com/forum/attachm...postid=2206681

 

could you explain what that is for us novices.....im guessing just a pipe connecting the non-matching cooling passages?

 

No I mean an external crossover on the back of the engine like the LT1 has. The intake on an LT1 does not facilitate the coolant to migrate from one bank of the engine to the other and thus has a cross over pipe that connects the coolant passages of the heads at the back of the engine. Regular SBCs use the intake to join the banks together through an internal passage in the intake. Some SBCs have that crossover in the front of the intake and some have it in the rear so the heads can do it either way (some aftermarket heads even have provisions to have a center crossover as well. The idea being that the more uniform the coolant temps in the head, the better)... But if you bolted an LT1 intake onto a SBC head you would not have any crossover at all since the intake and heads use conflicting methods to provide a crossover. My guess is you would need to drill and tap the holes in the back of the heads to make the crossover pipe from an LT1 (or the like) bolt up to a SBC head to give you a crossover passage. This could also be done simply with 4AN line as well. But I'm not an LT1 guru so maybe the other guys on here have more info/a better plan .

 

That means you have good heads. I just get sick of seeing guys talk about peak numbers when the mid lift numbers are so bad there is no point wasting all the money on them.


As for the just take the SBC heads and throw them on a LT1 block with a rear crossover, that doesn't really work out that easy.

The pipe that connects at the rear of the heads and then ends up in the radiator is just there to let pressure out and not a huge amount of coolant flows thru that thing.

The big differences on the LT1 vs SBC is the coolant crossover from the intake flanges and the deck surface is very different because of the coolant passeges going from the block to the cylinder head. Those are the big problems.

Bret

 

As bret said there is more to it then just adding the tube. My tube will come off the back two standard intake water ports