I need to max 260ci and be able to make 1000 hp on av gas for extreme durability engine. So far it would be nice to go with an alum 5.3 destroke it but not sure if the alum block can take it. It is in a boat so I have an unlimited supply of cold water. Not if it can really be done as I would be limited on the heads from the small bore. looking for some thoughts on how a guy would approach it.

 

I know I saw an article where Keith dorton did this for a land speed car with an sb2 block and heads. You can find the article on hot rod and other magazines. That was with a pro charger I believe. One way or the other it prob a ly won't be ultra reliable without a lot of aftermarket parts.

 

I thought about it and instead of just a basic answer like my previous one I think an lsx block. 4.065 bore with a custom 2.5 stroke crank make 260 cubes. Forged bottom end. Find the best flowing heads you can afford. Custom cam little John or Martin at tick. Holley high ram. Twin turbos precision 6266 maybe. Air to water intercooler. Holley dominator control system. All that would make a reliable 1000hp. It can be done cheaper but less reliable. Honestly 1000hp from 260 cubes is a lot to ask in the first place then throw in very reliable and it won't be done with any stock parts in my opinion. It will be expensive to have small cubes with big power and reliable. IMHO.

 

I hear you. throwing in a 2.5" stroke crank is going to be custom anyhow so custom rods and pistons in no big deal. and lsx block at 4.065 i Think would be plenty,would just like to keep it lighter if I could and I would have to keep the rpm reasonable like 7500 max.

 

Send a message to Pantera EFI. He has done a lot of work with big power endurance boats from what I remember.

As for 260 ci, that would limit you to a 2.89" crank.
The aluminum block should handle it fine with that short of a stroke, especially with a good rod/stroke ratio. Less force will be exerted on the block itself.

 

As Joe says, no reason why it cant be doable on a factory alloy 5.3 block with short stroke.

Sure that big bang thing made near 1k on a 4.8 and they didnt blow it up despite multiple dyno pulls, and that was a stock motor ?

So building one properly shouldnt be too hard

 

Bringing this back as I have done a bunch more research. So looking at a 5.3/4.8 block maybe the 5.3 alum. 9:1 comp 3.9 bore 2.7 stroke. Vortech v30 102 or a 105, air to cold water intercooling, e85, tfs 205's, peterson dry sump with billet pan, 20psi boost should get me close to 1100 fwhp@6900. Is it going to live and what do I have to do to keep the heads on with the 4 bolt pattern? Planning on ICS titans if I can get away with it or titan pros and oring the block. Or am I screwed and have to go to an aftermarket block or lsx with the 6 bolt pattern? This thing has to run at WOT for periods of up to 30 minutes.

 

Are those ICS gaskets proven ?

Good strong heads, big studs. ie 1/2". Oil jets for the pistons would be a good call.

As for whether it will last 30 minutes....big question. The lower compression, and mayhbe aim for higher boost with a little less timing than pushing it hard the other way, should help keep cylinder pressures a little lower over a long er period which will help longevity, than trying to push timing to the maximum

Back on gaskets...didnt one of the US companies start selling some of those "pyramid" rings that Andreas had used ? Composite gasket with these rings that effectively bite into the head to seal. Although it does turn the head into a consumable to a certain degree.

 

I do not know if the ics gaskets are proven or not. The theory is good.lol
Yup was planning on 1/2" or at least l19 head studs.
Piston squirters for sure either journal type or katech style.
I could go less comp but was thinking that was pretty low already for E85. One thing is that this engine will have a ton of cooling in both the block and the oil.
I Have not looked into pyramid rings before but I have used cooper rings before and did not like them. They worked ok once the engine was hot but leaked everything when cold. I would guess the pyramid rings would be better as they don't rely on heat to seal.

 

Why not keep the bore factory 4.8/5.3 and destroke it a little more? The block will be more rigid and ring seal will be better.

If you have massive amounts of cooling capacity with the lake/ocean water, maybe consider half filling it to further stiffen the block up. Better ring seal = more power

 

Contact DBRODS on head gaskets with sealing rings. What is deck thickness on those TFS heads? I'd look at thickest deck possible with 1/2" studs. Half fill not a bad idea. With oil, water and air temps in check, conservative tune, just pray that after 30 minutes the engine diaper isn't filled with scrap metal for the recycler or the hull doesn't have a monster hole in it.

How often will you tear down the motor for inspection?

 

As far as bore goes I was just trying to unshroud it a small amount and try and make it fit a few more heads. but ya it could be left closer to stk. Filling the block half is a good idea and sounds like a plan. Will do on the head gaskets as that is a big concern for me. Maybe staying with the iron block would give less deck flex? I would rather have the alum block if it will work though.
One other thought. How high of rpm can I twist it and still go with a hyd roller being that the cam will be low to mid.6 lift max?

 

We usually pull them down every season so 10-15 hrs run time. Most NA engines will go about 40-50 hrs before they are in desperate need of major work.

 

A little more research and the TFS heads do not look like the best. So AFR or Mast from what I can see. Mast 225 are an 11 deg head 3.89" min bore or AFR 210 are 15 deg with min bore 3.9". The 3.78" stk bore kinda screws up the head choices. Thoughts?