Hello everyone, i plan to build a 5.3 out of leftover parts from a gen 3 4.8 (lr4) and a 6.0 (lq4) for the basic “big stuff” i will be using the block and pistons (same as 5.3 minus the dish) from the 4.8 as well as the 706 cylinder heads. i will be using the crank and rods from the 6.0 to turn the 4.8 into a 5.3. this engine will be going in my future daily, a 2nd gen 2wd auto s-10 and will be run on 91 octane fuel. i want to reuse as many stock parts as possible to keep costs down but still make decent power. i will definitely be upgrading to a larger camshaft and i’d like to try my hand at some basic porting on the 706 heads. with the flat top pistons and 61.5cc chambers this engine will have about 10.5-1 compression ratio which is a bit higher than i’d like for a daily driven motor but i don’t see it being a huge problem. what camshaft would you suggest for this combo? i’m looking for a good increase in power and a lopey idle but i still want it to be drivable. what parts can i reuse and what should i replace/upgrade? i’ll be getting stiffer valve springs to work with the cam (again any suggestions would be much appreciated.) would the basic trunion upgrade be necessary/worth it for an engine such as this? i am trying to price this engine out so please let me know all the nickel and dime stuff (as well as any big things) i may be forgetting. also, what kind of horsepower should i expect to get to the tires through an automatic transmission with this combo?

 

The best things to do with the heads is a good bowl blend and multi-angle valve job.

 

 

Ryan, start yourself a new thread. There’s no good way to come into another thread and hijack it, and expect info going two directions, even with related subjects.

 

Are you planning on rebalance the assembly ? The 6.O crank is balanced for a heavier pistons . You would be better off to find a 5.3 crank , no need to balance !

 

my plan was to get everything balanced because i’ll already have the 6.0 crank. would this be cheaper or more expensive than buying a 5.3 crank and selling the 6.0 crank?

 

It depends but in my area it's $200+ up to balance . 5.3 is very common plentiful ,and cheap so look hard should be able to find 5.3 crank for $50 or less !

 

thanks for all the info! any suggestions for a cam?

 

Make sure you know what 5.3 the crank came out of ...... Keep it simple don't mix and match . If you have press pin flat tops and rods stay Gen 3 , if you get a gen 4 it will be floating and be heavy . Watch out for tween year example 2005 has gen 4 rods and should be 24x . Later are usually 58x

 

thanks!

 

OP, for a camshaft we would recommend our stage 2 truck cam SUM-8701. Specs on it are .523/.524, 218/227, 112+2. It will provide a noticeable lope with a low idle speed. It has -1* of overlap so daily driving and driveability won't be an issue. This can work as a drop-in cam with no springs required. Using budget-friendly NAL-12499224 LS6 springs will help extend the rpm range. This cam will work with a stock torque converter.

If you wanted a bigger cam then next up would be our stage 3 truck cam SUM-8713. Specs on it are .545/.545, 222/231, 112+5. This will have a steady lope. Stock springs are not recommended with this cam. We recommend the budget-friendly LS6 springs previously mentioned. This can still be daily driver friendly with 3* of overlap with a good tune and stall converter. You can get away with a stock converter but a 2500+ rpm stall converter is recommended.

We offer either of these camshafts in kits with springs or kits with springs and an install kit. You can view these in the "Related Kit/Combos" tab within the overview of the camshaft.

 

.523/.524 can still use stock springs? I thought about .500 was the limit.

 

awesome, thank you!

 

SUM-8701 has similar valve timing and max lift as the GM Hotcam. The Hotcam was designed for use with factory LS1 springs. While .525 lift is ok, we like the added pressure of an LS6 spring (that is good for .560 maximum)when we can get it. An even better Beehive is the TFS-16918-16, but then you’re getting into more money. Of course, either require the added effort of swapping springs.

 

OK thanks! I totally agree with using a better (LS6 or similar) spring at those lifts. I just thought stock springs might bind at lifts over .500 or thereabouts.

 

Don't worry about 10.5:1 compression. That's nothing really. Especially if you're doing a cam, and especially if it isn't going into a massively heavy tow pig truck.

That's below most stock compression now days.

My current truck is 11.0:1 stock, the 6.2 is 11.5:1

I'd actually try to go closer to 11:1 if this was my build

On the heads, drop them off at a competent performance shop and have a valve job (3-5 angle) done and bowl blend. Possibly mill of a little depending on your compression preference. The valve job and bowl blend costs less than port work and gives you a lot of the power you get from a full blown port job.

Rockers, use stock ones if they are in good shape.

Horsepower... hard to say because of not knowing what trans wheels tires etc but you should be able to get in the mid to upper 300's at the tire pretty easy with a cam and a little bit of head touch up and some compression. That would be with headers good exhaust and a good intake manifold. The LS6 manifold is excellent for saving money since you can keep a stock throttle body on it and easily run a cable drive throttle body. The TBSS truck intake is nice but you have to have an adapter to run a cable drive throttle body since the intake was made for an electronic throttle body. And you'll need a 90 mm throttle body. But the LS6 intake with the 78mm throttle body will still make excellent power here.

You'll also be okay if you just slap on the 706 heads. For a tiny bump in compression you can get the WS6 store gaskets that are .045 thick instead of .051 like the OEM gaskets. You'll get a little better quench which helps prevent detonation, and a bump in compression. Win win situation. Plus they cost the same as OEM. Win win win. However, I'm not positive if they make them for the small bore truck motor. Check with them.