I have a 71 Cutlass convertible I a restoring. I have a 5.3 out of a 2006 truck with about 60k on it. The car is going to be a street machine, no track use.

My limited plans so far are, T56, 3.73 gears, truck intake and cam, headers and f-body pan. I'll be running 17 or probably 18" wheels as I'm using c6 brakes. The gear isn't set in stone, I am converting from an open diff so I can get what I need. I'll be buying a cam as the engine had a lifter go bad and damaged the one in it. I'm planning on contacting a sponsor for specific cam recommendation. I'm looking to get good power out of it while maintaining reliability for longer trips. The motor has 706 heads on it, but I also picked up a clean set of 243s, fuel rails and injectors off an ls4 this weekend. I have the truck rails and injectors as well. I want to run this on plain pump gas.

The motor isn't complete, I need knock sensors, front cover, crank pulley, and probably a few other things. I'm planning on truck accessories and have most of that now.

I know I need a cam and lifters and ARP bolts. What else should I replace?

Can I get 400-450 crank hp without spending a fortune? Will the 243 heads on the 5.3 work better than the 706?

Thanks!

 

243 definitely better. Will want to mill them down to 59cc for good compression. Long tube headers, ls6 intake. Fast 92 if you can afford it.

With the right cam you can hit the power goals.

 

Thanks for the help.

I was thinking about using the truck intake because I heard it is good for low end torque. Is this not a good idea?

 

oh it's fine for that. The truck intake is still better than the ls1. If you can get a deal on a trailblazer SS intake that's your best bet for a stock intake with good torque.

 

400-450 FWHP good/achievable goal. I would do a stage 1 port
Of the 243s with like AI. Shoot for 10.5-11.0:1 Compression 61 CC?
Contact Kip @ CAM MOTION for a custom spec cam something
Like 221*/225* .595"/.585" 114*+2*. have truck intake ported
By Peak Speed or best LSXRT MAMOFIED, worth a lot of HP and
Torque throughout your whole range (1500-6500). 1 5/8" -
1 3/4" LTs max. 3.73:1 excellent with a T56.

 

The 243 heads will get you around 10 hp over the 706 heads all else being equal

 

Thanks for the info. I'm not an auto tech so I don't know what the cam specs mean, but the info is helpful.


Great. I'm glad I picked them up and the yard had already pulled the motor from the impala so it was simple.

 

Another question regarding this. If the ss intake is good would that be the same as on a Buick Ranier with the 5.3? I think I can get one of those pretty cheap. And if I got that would I need the TB or use the one I have?

 

I don't know for sure, but I don't think it's the same. I think the trailblazer intake was for that one specific vehicle. A lot of people ditch the truck intake, because it's "uglier" than the car intake. There is a thread in the external section regarding how intakes perform that is worth a look so you can see for yourself how well each does.

On the throttle body question - some are drive by wire (throttle controlled by a motor and sensor in the gas pedal), others are drive by cable (steel cable between gas pedal and throttle cam). When I put the LS2 in the S10, I kept the drive by wire set up, because it was what came with the motor, and the throttle was bigger. To be honest about it, I prefer drive by cable, and I think it's easier when doing a retrofit. There are 3-bolt and 4-bolt throttles out there as well.

I guess that's a really long way to say - use the throttle that comes with the intake you get if you can. Unless you go aftermarket, in which case the vendor will make sure the parts bolt up.

 

On a 5.3, 59cc is 11:1, which will run very well for you, but use premium. AI port and mill job on your 243's will run $1K, and it's a good deal for what you get. The PRC 706 heads are also a good option without blowing the budget.

 

Trailblaxer SS intake was available in 2006 (I believe) on the Trailblazer SS and equivalents. It became the standard intake on all trucks in 2008 (I believe).

It is GM p/n 12580420 and can be bought brand new for less than $140 (Amazon, Rockauto, etc), and bought used with fuel rails and injectors for about $150-$180 (local to me).

Look for pictures of it online, it is very recognizable relative to the old style truck intakes.

 

that would be a bad *** build with a turbo on it. truck manifolds, ebay turbo, wouldn't be that expensive.

 

That thought has been on my mind. My son's built or help build a half dozen or so turbo cars. He says turbo everything. My hesitation has been that I have to pay for body work and paint since this is a full resto. We can do all the rest.

 

I just checked with rockauto and the 06 and 07 Rainier uses the same intake as the Trailblazer SS. I'm going to check on the year of the one at they yard.

Thanks for the help everyone.

 

The fwd 5.3l intake is the worst available.
The truck intakes are just better than LS1 don't let the f-body guys tell you it is a torque thing, they are just better period.

 

@96capricemgr I have a truck intake, I just got the heads and fuel rail and injectors off an impala. I got the fuel rail because it's a lot nicer looking than the truck ones. I'm don't think it is the one from the 06 engine I have. I think it was from an older engine, long story.

It looks like the yard has an 06 Rainier. Should I get that intake and TB? Do I need the fuel rails or can I use the one from the ls4? Anything else I need?

 

Yes. Raises average torque across the board, which also calculates higher horsepower curve.

 

Yes but the vast majority of f-body owners pretend it is torque gains down low and that it doesn't help up because it is lowly truck crap.