Casey James Gros

Have the opportunity to get my hands on an iron block 6.0 out of a truck. Going to bore it to get the 6.2L displacement. Plans are as follows, 243 heads, forged rods (reccomendations please) 4.8L crank, LS6 intake, and im unsure of cam spec yet. Has anyone done this sort of setup? Im looking for info on stroke and cam suggestions, it will be going into a regular cab short bed street truck. hoping for 450ish to the wheels. I know the bore for 6.2L is 4.065 but what would the stroke be with the 4.8 crank? Would it be beneficial to do the 4.8 crank? Looking into doing it because higher revving is possible due to the destroking of the engine.

cookseyb

You will need to use the 4.8 rods with the 4.8 crank ie. it will have the same stroke as the 4.8

Utinator

With the 4.8 crank, the stroke would be 3.267". With stock 243 heads, the compression ratio would be about 10.18:1. That's close to the compression ratio of a stock LS1.

I think you would be better off keeping the 6.0 crank. That would give you a compression ratio of about 11.18:1 with flat top pistons and 243 heads.

Another option, would be to just go ahead and order a stroker kit. With a 4" stroke and 4.065" bore, your compression will go up to about 12.24:1. If you're not comfortable running compression that high, you can keep the 317 heads (72cc). That would give you a compression ratio of about 11.29:1. The stroker kit also takes the CID up to about 415. You can easily exceed your goal that way. It will also give you more low end torque, which is what you need in a truck anyway.


If you're only looking for 450ish to the wheels, then the stock rods/crank will work. I just wouldn't use the 4.8 crank in a truck.

Casey James Gros

Only things that come with engine are 2 cranks (4.8L and factory 6.0L), block, and 243 heads. No rods, no pistons. The 4.8L crank is brand new from a shop in houston that i cant remember the name of, but my buddy bought all of the stuff to swap into a 350z but realized it would be too much work. He said using the 4.8 crank would destroke the engine and allow it to reach upwards of 9K RPM, im not worried too much about torque as it will be a race/street truck, going for more horsepower than anything. I would like 450 rwhp, but my only real goal here is to stay within my budget of 7K including cost of everything. Excuse my ignorance as ive only owned diesel trucks for the most part and not really familiar with the gasoline performance world. So in all, 4.8L crank would be on the opposite side of what im looking for? Or could i make it work?

Utinator

Not many people have used a 4.8 crank in anything other than a 4.8L motor. I don't know if you could reach your goal with the 4.8 crank or not. I do agree that you could turn more rpms with a shorter stroke, but I don't think that always equals more wheel hp. Peak hp in most LS builds starts to fall off after 6k rpms. You might be able to stretch it out to 6500 with a shorter stroke and bigger cam. I don't see the point in aiming for 9k rpms though. I've never heard of an LS motor going anywhere near that level of insanity.

Most stroker kits cost about $2k. Most cams are about $400. You could easily stay within your budget if you can do some work yourself.

With your goal and the parts you have available, I would use the 6.0 crank. Then, I'd order these parts:
-Flat top 4.030 bore pistons -----------------------> $655.99
-Matching rods (6.098" for 3.622 stroke) ------> $465.00
-BTR stage 2 cam -------------------------------------> $389.00
-Valve springs/retainers ------------------------------> $350.00
-FAST 102 intake---------------------------------------> $850.00
-Nick Williams 102mm Throttle Body-----------> $369.00
-Misc. seals/gaskets/hardware--------------------> $600.00
-I'd get the 243 heads ported ----------------------> $1000.00

Total: about $4,679.00

NOTE: Prices above are estimates, and for brand new parts. Some items can be bought used for much less. This should give you an idea of what it would take though. I recommend contacting the WS6 Store, and asking for a better estimate. Their techs will also have a better idea of what "misc" parts will be needed for this build.

NOTE: I listed 4.030" bore pistons above. That gives you a CID of about 370/6.1L. I know you really want 6.2L, but boring that engine out .065" might be risky. An sonic check should be done before boring the engine or ordering any parts. The .030" bore should be reliable.

Casey James Gros

Thank you for the info, WS6 Store told me im fine going up to 6.2L displacement and also reccomended I use the 6.0L crank. He got me set up with everything for $1800 out the door. My budget (including cost of the truck is 5-7K) so sorry for any confusion that was there. Engine build is going to cost approximately 3K doing all the work myself except for bore work. Unsure if heads will get ported or not yet. I think the only thing that was not included in the quote was valve springs which he said would be $100 but i may be wrong on that. Any advice on a cam to use? Want to go TSP since theyre kind of local to me.

Utinator

I think the BTR stage 2 would be a good choice. If you insist on TSP, then I'd recommend the TSP 228/232-112+2 .600"/.600". It's close to the same specs as the BTR stage-2.

This probably won't line up, but here's the specs of these two cams:
EVO EVC IVO IVC Overlap

50 2 4 44 6 TSP 228/232-112+2 .600"/.600"
52 2 2.5 44.5 4.5 BTR-II 227/234-113+2.614"/.576"