Paraman1

So I recently bought a 5.3 Vortec motor for my 64 El Camino . I am a complete newb when it comes to the Vortec and LS motors but have been reading all I can . Current plans are to ditch the 862 casting heads and ad some 243's ( I believe I have these purchased at this time) . Beyond that I am not really sure , I have read that the 243's need to be decked a bit to keep compression on the 5.3 up especially since I have no plans to put any boost on the motor so this is on my list of things that may be done .

I have also read that the truck intake is pretty tough to beat no matter how ugly it is so my plan was to buy or build a cover for it but again if there was a cost effective upgrade I would Love to look at it .

Not sure what I am going to need to do for an accessory drive but I have been looking at the ICT Billet kits , anyone have any experience with these ?

I am going to use a adjustable bracket with stock motor mounts for a mounting solution but haven't decide for sure what I am going to use there .

For an oil pan I am thinking the Holley 302-2 should fit fine .

I don't have any idea on exhaust but would like something mid-length so I can keep the exhaust tucked up as high as possible .

Last but not least is a cam to take advantage of the heads and exhaust upgrade .

In a perfect world I would hope with a decent tune I will be making 350+ HP with a pipe dream number being 400 HP with decent gas mileage and street manners .

Any help you guys could give me on this adventure would be great and I look forward to learning more and seeing things I may have missed .

Darth_V8r

iTrader: (4)

243 heads are great on a 5.3. Mill .020 should be about right. Use .040" head gaskets to tighten up quench a bit. Call Kip Fabre at cam motion for a good drop in cam to work with stock 243 springs and rockers. I used dirty dingo brackets for my S10 (see sig pic). You might end up needing corvette accessories. Definitely the Vette AC compressor. If you need clearance between engine and radiator the Vette water pump is nice.

350-400 on a 5.3 is pushing it if you're talking rear wheel horsepower. You'll need better heads to get there.

The LS6 intake is pretty good. Would be enough for your build.

Hopefully that'll help you get started.

Paraman1

Do you know who makes a .040 thick head gasket for the 5.3 ?

The 243's I purchased have a trunnion upgrade and Texas Speed 650 Valve springs .

I am looking to make 350-400 on the motor not RWHP .

Once the heads arrive I will contact the guys at Cam Motion and see what they have to say about a cam.

Darth_V8r

iTrader: (4)

Cometic makes a .040" with 3.910 bore spacing. That'll work well for you. Nice work picking out heads.

A.R. Shale Targa

iTrader: (2)

You can also look for some used 4.8 flat top pistons to swap in there which with the .020" or .030" milled 243s will get you in the mid tens for compression.
A cam in the 220-224 duration will easily hit 425 flywheel horse and 360 or so rear wheel

lazermule

What's the downer about the 862 heads? Are the 243's that much better. I'm doing a similar build but I have the 862 heads. I haven't started anything yet, but my plan was to use the 862's, have them decked, use 4.8 flat tops and a good cam match. my goal is to make at least 400hp. Is this doable? I don't have an issue finding some 243's if they are worth that much more, or some reasonably priced GMPP heads or maybe some other aftermarket pieces if the price is right.

The application will be in my daily driver Jeep TJ Rubicon backed by a 4L60E.

Thanks,

LM

gagliano7

If you send your 862 heads to get ported you will do better than stock 243 heads and have more compression. http://www.texas-speed.com/p-1172-pr...-castings.aspx

Here are the flow #'s for the 862 heads ported by TSP
Lift____intake____exhaust
.200____147_______111
.300____206_______145
.400____254_______185
.500____291_______204
.600____308_______223

KCS

iTrader: (20)

With these heads all being over a decade old, there is a lot of information on this site if you just use the search function...

In a nutshell, the 862/706 castings have smaller valves and not as good of an intake port as the 243/799 castings. However, since they're usually about $300 cheaper, you can usually have a little work done to them and make them a little better than the 243/799 heads for about the same money.

lazermule

Does it make sense to install larger valves in the 862's? Or is that gain negated due to the 5.3's bore size? Or is all of the gain found in porting?

Thanks,

LM

KCS

iTrader: (20)

Yeah, definitely makes sense. Some of the 4.8/5.3L engines came with 2" valves. Ported 5.3L heads almost all use a 2" intake valve or larger.

Some of the gains are in the porting, some are because of the larger valve and better valvejob, and some are from the smaller chambers.

vetterme

Hi,my ls1 corvette has factory 862 heads,and these heads seem plenty good.I sure don't know everything. But chevy done odd things sometimes...so do check your vavle size no matter what number head it is............its like the old chevy heads from 60s&70s..everyone wanted double hump fuel heads........but 186-492-041 heads all different numbers but came with 1.94 and 2.02 intake vavles and all flowed about the same just sayin! Now also remember if vehicle is heavy you might want to keep a smaller vavle so u have the torque for weight . Now remember i'm old school,but just started using new school ls engines 5 yrs ago now. And i'm very happy. One things is certain we never stop learning. And if you need anything for your 5.3 motor or even a spare I have 2 ....1 long block...1 short block both under 21,000 miles, and I have ls1 heads..5.3 ls heads,if u need anything give me a shout.