I've heard some rumors that some guys are taking 4.8/5.3 short blocks and putting large throw cranks in them and making massive strokers out of them. I have a 4.8 block so I'm curious about it. My question is how much throw can you put in a 4.8/5.3 block and be safe and how many cubic inches you can get out of it. Is it worth the effort and the money? If any body has any ideas it will be greatly appreciated.

 

While you would see some gains, spending money on a stroker kit would not be as productive with the 4.8/5.3 case. I would think that valve shrouding (and it's accompanying effects) would be an issue with the smaller bore.

 

not if you used a properly sized head like a AFR 205 or TFS 205 or even a ported 5.3 casting

i want to say wiseco makes pistons for a 3.78" bore and a 4" stroke with a 6.125" rod (359.1 ci)

if you used custom pistons you could use a 3.875" stroke crank (347.9 ci) or a 4.125" (370.3 ci) i dont know if that would fit though

 

The valve shrouding was somethin I was concerned about. I was only considering it because I could put the short block together for about 1000 bucks.

 

Hello motor crazed poeple , there is an article in a hot rod mag from about 10 years ago titled " The 350 Chevy should have built " . It would be worth you're while to go to Hot Rod's w-site and look up the article and read carefully . Basically these engine geometry wizz's take a sm 400 block bore it .030 to 4.155" put a 307/327 crank 3.25". Ford 300ci 6cyl. rods 6.209" narrowed at mach shop to fit Chevy crank . JE pistons w wrist pin loc higher on piston probably dome pistons also .Aluminum heads w 58cc cham netting 11/1 comp. a "Folley" "Holley" carb I believe 750 dbl p. a stock lift n dur roller cam. a GM hei and headers . On pump 87oct , 36deg total ign adv 435 lb/ft and 412hp. By my calculations, a similar gen 1 350 w 11/1 comp and the rest as close as possible except for the bore and stroke and the long rods, would produce roughly 235 hp and maybe 300lb/ft. So I imagine engeom wizz's engine with a cam and maybe tpi or sfi or a killer aftermarket multipoint fi that engine would be pretty awesome .
So , I believe the 4.8l crank n rods in a 6.0 block with 6.0 pistons might work just like it is . I know the 4.8l rods are right at 6.25". You'd end up with basically a 5.3l with much better flow than gen1 . Or bore that 6.0 bl and maybe make a better 350 than enginegeometry wizz's . No doubt the engine would rock as long as the pistons come right up to top of block deck flush . Good luck

 

You can order a fully assembled stroker short block for not much more than the cost of machine work and piecing together a stroker. That said, most 4.8 blocks can be bored to 3.900 or 3.905 (basically 5.7 LS1 bore). Then get a forged stroker rotating assembly with a 4" crank (might need a machine shop to clearance the block for the larger crank counterweights). This will give you a 383 CID engine.

 

Im not sure how strong the 4.8 cranks are but....Something cool would be to take a Lq9 block and put a 4.8 crank in it with forged rods and pistons. With supporting valvetrain, you could rev that thing to the freakin moon! I know thats not the OPs question but it would still be cool to do!

 

as stated... just bore it to 3.898-3.905 with a 4" stroke. I'm building one as we speak for a project car.

 

if u really want ci. the 6.0 is the way to go. why spend on building a smaller displacement stroker when can have a 408 for about same price.
it takes more metal removed from 4.8/5.3 bore block than 6.0 lq block. lq can go up to .060 or 4.060 bore.
it will probably cost more to have 4.8 block machined since more metal has to be removed than a 6.0.
my 4.8 with low scr built for around 20psi.
0.02$

 

I talked to one of the Guys at Long Race Engines in Irving Tx the other day about stroking my 5.3 and they told me they dont have to remove that much metal to make a 4" crank fit in the 4.8/5.3, said they do it all the time. Just my 2cents

 

Forget it. You can get a good used 6.0 engine cheaper than you can get any LSx forged steel 4" stroke crank. Let alone rods and pistons. Better put the rods and pistons money into better heads. And the bigger bore will improve flow, whatever heads you use. The 6.0 will out-HP the bored-and-stroked 4.8 block, which, coincidentally, comes out at 383 cubic inches. There is a cast stroker crank available, but it's not for what you seem to be wanting.
Chris Frost is obviously new to LSx, stuck on SBC. Things have changed. LS1, LM7, et cetera all come with the pistons 0.010" out of the block at top dead center. And 4.8 rods are not "right at 6.25"", they're 6.275".
Trying a 4.8 crank with a big bore would require Mallory metal to fix the balance, but 4.8 rods and LQ9 / LS2 or LS3 pistons would work.

 

so do 5.3/5.7/6.0s all have the same crank?

 

Here was the reason why i went with the 5.3L build instead of the 6.0L.

The 6.0L costs around $1000-$1300 depending on mileage and "your" specific area and market.

I picked up (2) LM7 5.3L for $350 (one ran with 250K and the other had a owner induced intake fire, so i assume it would have ran fine)

The machining costs and gaskets needed between the 5.3L and 6.0L we will call a general wash even up cost between the both of them.

The 6.0L i assume will be bought running and installed as-is with no internal work performed.

The 5.3L would need cam, machine work on block, crank and maybe heads. I bought a set of 243's. New pistons (5.7L versions) will need to be bought and then the odds and ends (bearings, timing chain, etc.)

So i have $750+ "extra" to spend on the 5.3L to 5.7L conversion vs. buying a USED 6.0L ...... and I will have a brand new motor vs. a USED 6.0L in my car.

General rundown:
Pistons/rings $275 set (not forged)
Crank reground $90
Boring $20 a hole ($160)
Block cleanup and deck machining $100
gaskets/seals/head bolts ($225+)
Cam crank rod bearings ($125)
Lifters/pushrods ($225)
Intake LS6 ($300+) depends on the deal you find
Injectors ($ ???) depends on what you want
baance rotaing assy. ($ ???) depends on your area.
other misc. costs that will pop up.

So im going with this and have a new motor that should last alot longer that the 6.0l assuming the used 6.0L had a substantial amount of miles on it. You never know if people ever changed the oil on a used engine....or ran it with a compromised cooling system or god knows what.

Ive bought plenty of used engines and got many great deals and runners so im not knocking them...im just saying i prefer to have a new one in this case.

Of course i would go with a new 6.0L or rebuild one if i were putting it in a truck used to haul often OR in a car that spent most of its time "earning" money on a track but thats not the case for me.

So 5.3L converted to 5.7L is it for me.

 

yes? no?

 

My 6.0 was built to displace 375ci 4.060 bore
Stock crank
Stock rods with speed pro hypereutectic lq4 replacement pistons with matching speed pro rings
Very good cheap pistons. Very reliable. Take alot of abuse.
Self ported and machined 243s with rev 2.02 valves and stock exhaust valves
Cometic gaskets
Custom grind cam with jesel ss 1.7 rockers
Arp rod bolts and head bolts
Stock ls6 intake. 80mm tb
A very detailed SD tune
All supporting bolt ons.
Car made 490rw na at 7200rpm thru stock 10bolt and t56 thru spec clutch
Shifted at 7200. Was a dam fun motor. New owner has fast 90/90 and ewp and is over 500rw now
Engine has bout 5yrs now. Prolly like 30k+ miles now and countless track runs.
I love the 5.3s and 4.8s for forced induction. I have a low compression 4.8 and currently building a 241 heads heads studs 5.3 for swap with Procharger for friend.

 

the 5.3/5.7/6.0/6.2 all share the same 3.622" stroke but as I understand it each motor has a different crank due to the different weights of the piston/pin/rod assemblies .