Bubba15c

Have a lq9 block bored .40 over and have some questions. Could i get away with running heads off a 4.8 or 5.3 with aftermarket springs, rockers, push rods etc and a 228 cam or should i go bigger/smaller? Would like to make 400 wheel hp. Or should i build a 4.8 that i can ****** up for cheap? What could i do to that to make around 350 to 400 wheel hp?

G Atsma

For that engine I would look for a set of 243/799 heads. They came on most if not all 4.8/5.3 Gen IV engines, so are easy to find.

Ls7colorado

iTrader: (3)

whats the budget?
Is the 6.0 block assembled and ready to go?
And I agree with above get some 243/799 heads they are getting cheaper and cheaper

400whp is so easy with a 6.0 and can be done with a 5.3 if you dont mind rpms

Bubba15c

The lq9 isnt assembled got it in pieces. Just block pistons/rods and a cam. If i get a set of heads you mentioned should i put different springs/pushrods/rockers in them or not even bother? Just trying to get opinions on parts right now so when i do have the money to spend i wont waste any time lol. What about 400 with a 4.8 n/a?

Ls7colorado

iTrader: (3)

http://www.ws6project.com/user_stor/...oducts_id=8670
Id get something along the lines of that cam/springs and you will want to add hardened pushrods
A rocker arm truniuon upgrade would be a good idea but not 100% necessary with that cam

Not to sure about a 4.8 build, I dont see why you couldnt get 350rwhp out of one someone else might can comment on that

whats it going in? what are you gonna be doing with it? What transmission?

jetech

Welcome to the site Bubba, what vehicle will this engine build be powering ? If it is a heavier type vehicle I would go with the 6.0l for the bigger torque numbers. What will be the vehicles main purpose ? Agreed with G Atsma and LS7colorado about the 243/799 heads. Yes for aftermarket valve springs, Stock rockers are very good just replace the stock needle bearings for trunion bushings and measure for the correct pushrod length after you have the heads reworked, choose which lifters and the head gasket thickness you are going to use.

Bubba15c

Going in a 2wd c1500 so not too heavy. Not sure if i want to go auto or manual so would be between t56 or 4l80 or something along those lines.

Bubba15c

And itll be mostly street use but maybe strip once in a while.

jetech

I wouldn't even consider a 4.8l if you are staying n/a if it is in that large of a vehicle and you are wanting 350-400 @ tire hp

Ls7colorado

iTrader: (3)

completly agree, way to heavy to have any fun with a Na 4.8, now if it was a Miata or S10 or something .......... id say go for it

just do the 6.0, 243 heads, decent cam, springs, push rods ect, and let it eat

Bubba15c

Alright. Thanks guys appreciate it

00pooterSS

iTrader: (40)

Are the pistons flat tops?

To give you some ideas

With 61 cc heads (706 or 862) you'd be at 11.77:1 compression with flat top pistons and GM gaskets that measure out at .052. With ws6store .045 gaskets you'd be at 12.0:1
With 64.5 cc 243/799 heads you'd be at 11.25 with the same head gaskets. With ws6store .045 gaskets you'd be at 11.46:1

You'll need to run premium fuel for all the above

And those numbers are using 0.006 piston out of the hole. That can range a little but not much. If they were another .002 out (0.08 total) compression would go up .06

As for which trans, it would be easier to go auto and be faster, but the standard would be more fun to just drive. Well... that's personal preference, I like stick cars to drive and autos at the track. And the better these autos get and the older I get the less I care about a standard anyway.

Bubba15c

Part number 1000600 auto tec dished/valve relief pistons.

Ls7colorado

iTrader: (3)

Bubba15c

Oh ok i misunderstood them then. Thank you

00pooterSS

iTrader: (40)

The 3.3 cc for valve reliefs drops compression .4 so apply that to the above numbers.

All my compression numbers are from Summit compression calculator if anyone is wondering

With the 243's and .045 head gaskets you'd have .037-.039 quench height and 11.0:1 compression. That would make for a really nice setup and the reduced quench would help with ping. Be a fun motor. You could go higher on compression but 11:1 is a pretty good all around number for a street car.