so i have a track car and weight / weight distribution is pretty vital

recently my motor had some overheating issues. leakdown test was not conclusive. the motor could have warped head/block, blown gasket, cracked water jackets. at this point the block is tore down. 04 ls1 with a tsunami cam and prc stg 2.5 ls6 heads

money is always a concern on a tight budget but at the same time i want the best bang for buck

the options and concerns are listed below

1) Acquire used ls1 shortblock and mill my heads and swap cam/head - unsure of reliability/condition of used motor and how long it will last me. could possibly end up with another motor that needs be to machined

2) rebuild current block and purchase a 383 stroker and mill and swap my heads/cams - unsure of condition of block, could possibly waste money at machine shop for a block that isnt worth salvaging. Also the power gains of going w/ a 383 are not substantial enough to justify the cost of machine work and parts.

3) Purchase an iron block 421 or 427 and mill my heads and swap cam/heads in - weight may be an issue, does anyone know the difference between iron vs aluminum block weights?

4) Purchase an aluminum 418 ls3 block and mill my heads and swap cam/heads in - this appears to be the most reliable however also the most expensive of the options.

Any help / suggestions or ideas would be greatly appreciated.

 

You can get 408 kits for s 6.0 iron block for a decient price. The iron block weights 87lbs more than the aluminum block....but with the added displacement it makes up for that weight pretty quick. (I went with a 408 in mine and love it)

 

I take it you are road racing. If weight distribution is an issue, you can still use the iron block, relocate the battery, maybe change some front suspention components out for lighter aftermarket one to correct this. If money is an issue this would be the most expensive answer, but it will make more power. The nice thing about the iron blocks is you can rebuild them more times before the cylinder bores are gone.

I think you should send your block to one of the sponsors to this sight. Let them inspect your block and see if they can salvage it. If not, I bet they can get you rolling fast with another one that they will back, and not kill you with price.

If you go to the larger displacement iron blocks or the LS3 block, you should consider upgrading your heads to match. But again, this will cost more money.

Changing our displacement will make more power, but you will have the added cost of larger injectors, possibly needing to upgrade the fuel supply system, tuning, more expense making the rest of the car stay together from the extra power, and taming the extra power with your suspention. If you are happy with your current power level and really can not afford to have to spend money on the other issues extra power will cause you, fix your engine or replace your block. I bet even if you buy a new block it will in the end cost you less then all the money you will spend taming the extra power level.

 

There is not much left to remove from the front end.
this is a track only car and even now we are still fighting weight distribution issues with the front end being so heavy. That is another topic altogether tho.

in terms of the larger displacement. wouldnt having the ported ls6 heads be a little go between until i can pick up some better ls3/7 heads...

i knew that doing anything other than a oe rebuild for me would require a retune and i am running 36 lb ford injectors and am no where near maxing out the duty cycle w/ the current setup

In terms of hp goal.
right now i am at about 400 whp
ideally i'd like to be around 550 hp/tq
with as much area under the curve as possible.

the budget is 6k however less is always better as there are always other costs.

 

Nice! I see your delema now. Not much left up front. Yes the LS6 head would work until you could upgrade to some LS3 L92 heads. You can get the L92 head dirt cheap but not as cheap as running your current heads until funding is better.

Texas Speed is showing a 416 LS2 aluminum short block assembley for 4300 bones. Run your heads, intake, covers, pan, and all excessories with it. Buy a nice cam and oil pump, 550rwhp should be easy to do with your LS6 heads.

 

I may be wrong but I have never seen 550rwhp out of ported 243 heads on anything. An ls3 headed block with a 4.0" or larger bore with right cam/intake/exhaust combo can get there but with a 6k budget and what it appears you have to work with it will be very tough.... Bottom line is to see 550rwhp you need 400+ cubes and better heads and intake than you have.....

 

instead of going w/ the 416 ls2, how about the 429 ls3?

and if i do go ls3 i could keep the current heads and current everything else. until a later date or is there too much hassle going ls3?

sombitch.. 550 is a goal for future.. not necessarily to get up and running.
at this point i just need to get up and running and have a good baseline cu in block as a good platform to expand on later.
during the downseason i should be able to pick up some better heads and an intake.

 

the bigger inches will help. If you are road racing I would think the 429 would make tons more torque if cammed right. I do not know if the 429 runs a 4 inch stroke shaft or bigger. I have a 408 with the 4 inch stroke and take it to 7000rpm all the time. I have pulled the engine and inspected it three times now. I have never seen a single bearing or piston skirt issue with it. I do run Ross Pistons, but I would think the Wesco pistons are just as good and would give great service. I have seen lots of failures with the other brand pistons, but most of those failures can be atributed to other causes. Back to my point, I KNOW without a doubt you can turn a 4 inch shaft pretty high with alot of power on it (my setup is boosted and makes 844rwhp and 817 rwtq, going to 1000+ on both sides) and the 4 inch stroke is no problem in these engines. I have no experience with the longer strokes.

If the 429 is a 4 inch stroke and is built by a good vendor on here I would not be scared to run it. The bigger displacement will make you more torque for coming out of the turns, and it will tame larger cams which will help with tuning the car. The L92 heads are identical to the LS3 except for valve material. i run a set that is ported, but with stainless steel valves. You can pick the heads up from Scoggin Dickeys bare for around 300 each, and the for about 1000 a pair built. There are better heads out there but for the money they are very hard to beat. Still on your budget I would run the heads and topend you presently have until you have the funds to upgrade. To go to the LS3, L92, Ls7 style head you are going to have to change the intake, fuel rails, throttle body, and a few other things. Expect to spend 2000 on the low side for changing the heads out. The cylinder bore needs to be at least 4.030 to run the L92 or LS3 and a little bigger for the LS7 style. But I be the 429 bore is big enough for either. Check on the stroke of the 429 and if it is bigger then 4 inch talk with people that have run the larger stroke and see what kind of sucsess they have had. Also consider your rpm limit, then make your decision.

What is the price of the 429 short block youare looking at and who makes it?

 

I don't think you can say budget and road racing in the same sentence. You know that reliability down the road is what will cost you eventually. If I were you either got for it all and forget the $6000 budget and build what you want correctly once or spend the money on one or two GOOD components that will get you there in the future. Spend the money on a sleeved ls2 block that will give you longer skirts so you don't have to worry about the stroke, and if you have anything left over then the next thing I would look at is a high end lightened crank. You can make 550 rw as seen in the sig but how long that would last living at 5-6000 rpm is something I really wouldn't want to test for too long. A dry sump if you don't have it would also be a must.
JMO

 

currently i have this cam.
235/240 .648"/.609" w/a 112 LSA

the current motor before make its peak hp at 6200 without any dropoff after and i normally spin it up to 7k depending on situation.

so in terms of the short block.
the vendor would be texas speed

here are the specs for each.

429 LS3 4.07 bore / 4.125 stroke
418 LS3 4.08 bore / 4.000 stroke
416 LS2 4.005 bore / 4.125 stroke
402 LS2 4.01 bore / 4.000 stroke

and the reason for the tight budget is the tight deadlines, with the motor being down i am not representing the partners at the track. If i could wait 2-3 months i would just pick up a complete long block and everything else but that isnt an option at this point.

I have pretty much decided to forget about the ls1 rebuild or 383 stroker option.
so at this point picking up a new shortblock or getting a used ls2 bareblock and getting a stroker kit seems to be the options i have now. however regardless of which block i need to pay about 300 for the conversion for the knock sensors / covers / timing chain / etc..

 

Was reading your thread. In the same sort of delima your in,regarding new build v. budget. Just curious did you make a decision.

 

yup.. made my decision.. ended up playing an order for a 418 stroker ls3.. for n/a build..
gonna reuse most of my ls1 parts like head and intake and eventually will upgrade to a ls3 or possibly small bore ls7 head when the market has more head offerings..

 

If I were you, I would just find another LS1 shortblock and throw it in for now, just to get back on the track. Blow the rest of your budget on a good dry sump system. It really is necessary on a LS1 in an endurance application. Then down the road, sleeve the block you have and build a 454ci LS1 out of it.

Also, SAM was going 9.1's and making nearly 900bhp with 427ci and 243 heads almost a decade ago. They are very capable heads and I wouldn't quite consider LS3's an "upgrade".