ScorpioV8

I have a L33 with damage to one of the 799 heads. I have been offered a pair of 706 heads. Other than the chamber being different, could I swap them over or is this a backwards step?
799 heads are not plentiful over here in the UK, hence the reason.

Thanks

Gareth

oldguy99Z

iTrader: (2)

The 706 casting is one of the 5.3 L engine heads.It has a smaller chamber(a little more compression)but also a smaller intake valve(1.89")in its stock form.It would be a step back IMO.

ScorpioV8

Thanks, found suggested on the Performance trucks forum that you fit the 2.0 valve into the 706 heads. I'm just researching what CR I'd end up with.

Gareth

oldguy99Z

iTrader: (2)

Sure you could put 2.00 or 2.02 intakes in them.Those heads have a 61cc chamber stock so even after some work to open up the chamber a little around the bigger valve you still will have a smaller chamber than the 799s.Thats why the 5.3 L heads are popular to rework.I think a lot of the ported versions have around 63cc chambers when their done but that of course depends on how much is done to the chamber.With the bigger valve those 706s would be better but the 799s still have better ports.

intenseblue

iTrader: (1)

Can the head be repaired? That would be your best bet for performance

NemeSS

iTrader: (127)

Repair the head. The 799 is superior over the 706. It's a significant downgrade. Unless you spend alot in porting the 706s with bigger valves. And vj

ScorpioV8

A specialist welder has quoted me from a photo between $120 and $200, so looks like he can have a go at it. Anyone know what alloy the 799 is made of and how well it welds? He is an ACE welder and comes well reccomended. I have attached three pictures of the damage - exhaust manifold was wrenched out of the head by a side swipe. Pulled some head away, pulled some studs and their thread clean out, and snapped the front and back ones off in the head.

20K motor and trans though, with pcm and all the bits including cats and propshaft, about $1900....so I bought it

Thanks for guidance, it really helps guide meon this.

Gareth

ScorpioV8

Problem solved - found a pair of 241 heads that have had a 50 thou skim, all cleaned up and ready to fit :-)

Also scored as part of the deal an LS1 intake, rail, injectors, LS6 cam and springs for $225 I wish I could close deals like that every day!!

Gareth

sittinlovely

iTrader: (20)

where in england are you? If your close to suffolk, I know someone that can hook you up. The 241 is a downgrade as well to the 799/243 heads

ScorpioV8

I'm in South London, but am driving to Norwich (through Sufolk) on Thursday so could possibly sort something - pm me if U like. I know the 241's are not quite as sweet as 799's but $ wise they were basically free - I just can't find a 799 head over here, so if you can help, great. The 50 thou milling should bump up the cr a bit - still researching how much. Need to check that the LS6 cam won't make the valves meet the flat top pistons too with that much taken off, but nothing a fat gasket won't cure.

Thanks

Gareth

ScorpioV8

OK, On Performance trucks it says if if I remove 50 thou off a LS1 head I lose 4.9 cc, making what was 66.67 down to 61.77 cc, it also says its a 'good head for street and strip.....but not as good as a 799 I guess

Gareth