On mods I have more than what my car costed new.. so.. what is the difference???

I dont thing that a 7L with 650Flywheel HP requires that much in everything given the good heads.. supposedly with the GMMG zl1s and the ls6 heads they did 625 rated... maybe its less then...

When I said 600rwhp didn't mean specifically 600rwhp but just to put a high mark... I know 550rwhp is doable with mindgames heads and an lt1 383 not 427... so there is a lot to be gained in a few areas

 

Ah yes, cost. The one strand of reality that keeps 99% of the people on this board from having what they really want....but then, would there be an f-body?

I'm certainly in this conversation from a cost perspective still. A decent set of AFRs starts @ $1900. If inded you could get a set of Brodix 18xs for $2200 and the necessary work to make them fit for another $400, then throw in the intake work for say $200-$400 that still puts you up to the $3,000 in top end equipment area...certainly you won't see every high school or college kid giving up that much extra beer. On the other hand there are guys like me. I'm not going to throw HUGE bills into an LT1 project at this time...but if an extra grand will get me stuff that is a) much more useful and b) much more upgradeable for future use...it may be within the budget.

I haven't convinced myself these cost number are viable yet...though some are here are claiming them to be and I'd like to think so

 

From a cost stand point I don't see the 18x with standard exhaust port being any more expensive than the afr215rr. The afr raised runners require offset lifters and rockers, 18x uses standard 23* valvetrain..... Intakes would be the same cost-wise as neither 18x or 215rr work with a standard LT1/4 manifold.... I think, depending on conversion cost, that the 18x might come out cheaper, once valve train cost's are figured in.....

My biggest concern with the 18x would be the 245cc ports and how you'd get them to work with a hyd roller or without spinning past 8000..... Bottom end component selection is a different ballgame spinning that high at a horsepower level that could use heads like that.....

What is the crosssectional area of the 18x intake port anyways?

 

You would have to have big cubes... the lsx engines after porting they have around 240 intake ports.. but their ports are longer and they make the volume with length and not width.

 

I just did some surfing and found bare 18x standard port for under 1500, complete for just und 2000....

So Phil, since you think conversions are fun I'm sure you'd do a conversion cheap huh? Just think, we'd both be happy! I'd be doing you a favor..

Seriously though, I'd like to hear some thoughts on getting this to work on the steet, maybe in a forced induction application....

 

For a forced inductino application is not that "important" to have a set of heads with such fancy stuffs... all you need is a good flowing set of heads and boost will do the rest.. what are your goals??? 9s on 5pso boost?

Boost makes things a little bit easier in some ways...

FWIW on boost.... I got the LT4 afr heads and T-trim supercharger...

Really.. I would love to have all the power I have N/A... So which is why the need for fancy stuff arises.

 

I hear ya Highlander, 9's on 5lbs and pump gas too.... (I hope you can tell that I'm kidding about that)..... What I'm getting at is if you could get 18x heads to work for close to what you'd pay for afr215rr's than why not go that route.....

Like I said earlier, I think 245cc would be way too much port for anything other than a large CI solidroller.... I don't think there's enough you could do seat/bowl wise to make that much port volume work for you in a low rpm motor under 420+ cid....

 

The runner volume question is yet another bone to throw on the pile. I think I'll try getting some cross-sectional numbers, flow numbers, etc and put together a good desktop dyno assisted analysis. Some of the guys one here (SStroker) might be more successful @ giving us some real world feedback. Any takers?

 

Dont forget the 18* pistons. Custom big headers are really a necessity as well.

 

Serene, I'm talking about the brodix 18x std's..... Standard exhaust not spreadport.... This head does require an 18 degree piston though.....

We really need to hear from Kurt Tamez.... He's done this conversion....

 

When building a shortblock... it's not any more expsensive to use 18* pistons instead of 23* slugs. Obviously this is a moot point if someone is looking for a heads/cam package for their stock LT1... but what kind of 350 can use runners that large with a 7000rpm redline (PCM)?

IF someone goes with 18* heads, they'd probably be looking at a shortblock rebuild anyway.

For those of us building a "moderate" 383 though... using 18* compatible pistons (Weisco has several that fit 23 and 18* set ups) seems like good foresight.

 

FWIW, I'm running some Brodix -10s, converted to reverse-flow. I'm on the stock bottom end and I use the LT1 intake. I've never had the car on the dyno, but it pulls pretty hard. When rebuild time comes I hope to make the combination work together a little better. I don't think I'm anywhere close to maxing these heads.

302 cfm @.500
318 cfm @.600

 

several people have mention the TFS heads. i own a set of them, theyare the exact same as the standard sbc 23 degree heads converted to reverse flow cooling. they were delivered to the door assembled for less than $1300. for out of the box heads they aren't that slouchy 253/.500, 254/.600, and the average i/e ratio is 74%. other than cost one of the reasons why i chose them is the 62cc combustion chamber, it opens up a lot more piston options for better quench over the stockers while still having a some what decent compression in a stroker.

 

To see the new Trick Flow LT1 heads go here.

http://store.summitracing.com/defaul...00010&x=11&y=8

They are priced pretty decent.

 

I'm gonna give CFM a call on monday and get a set price on the conversion. this is what I wanted to do in the first place when I built this motor. I'll make it next winters project.


Neal