Does anyone know the intake port size of the stock lo3 head? I want to port match my tbi intake to the gasket, but I want to make sure that once this is done the manifold ports will not be larger than the ports on the heads. I will use the recommended gasket size and I have the edelbrock tbi manifold. Thanks for the help, Mike

 

Yea!!! What he said!! I have been trying to find out, but no casting # ref. charts tell the tale. What's the deal man?

------------------
92 RS w/t-tops 305 TBI Auto.
170K miles and don't burn a drop o'oil
-K&N Truck filter #1500 w, open ele.
air cleaner
-Dynomax 2 1/2" cat-back
-B&M TransPak
-Jet Stage2 Chip
-180* T-Stat w/ 185* Fan Switch
-JVC CD--Alpine speakers & 4ch. amp
Rockford 2ch. to 2 MTX 12" subs

 

Port matching the intake w/o porting the intake port in the head really will not help performance at all, in fact, it will probably hurt it. When porting heads and intake, you actually port the intake SLIGHTLY smaller than you do the head, about .010" or .015" on each side so that you don't create a "step" for the air/fuel charge to hit and began swirling, therefore creating turbulence. This is good for low-end torque and pulling but it hurts upper-end airflow and RPM capability. I personally would hold off porting the intake until getting new heads(because I also wouldn't waste the time and effort on porting the L03 swirl port heads) The intake ports in the head are going to be smaller than the recommended gasket, and if the intake manifold is ported to the gaskets, then intake ports in the manifold will be considerably bigger which is not what an already poor flowing head needs.

------------------
82 Z28 383, Ported 215cc Dart Iron Eagle Heads 72 cc Comb. Chambers, Comp custom grind Hyd roller cam, Speed Pro .250" domes, Wheeler Motorsports 4340 I beam rods, Eagle 5140 steel crank, Weiand Team G intake, Holley 830 DP, hedman headers
Trans: Turbo 350 w/ 4000 stall -- Rearend 7.5 w/ Richmond 4.10's, Auburn Minispool
Best ET:11.63 @ 113.25, w/ a 7.39 1/8 @ 93.04, and a 1.626 60'


89 RS, L03 305, Hypertech Chip,cat delete, Dynomax exhaust,K&N open element Filter,160 stat, MSD coil --Trans:700R4 Corvette Servo -- Rearend: 7.5 GM 3.42 w/ posi-lock
New Best ET: 14.91 @92.9
Bassett Racing

 

Anyone know, just curious? What about the exhaust ports?

 

Exhaust ports: try to create a slight step at the bottom of the port (head port smaller than the manifold or header port). On top, create as large a constant radius as possible. That is, if you cross-sectioned the exhaust port and manifold, you would want a large radius at the top. You may want to open the top of the head and manifold ports to achieve this. Don't just start cutting away the top of the exhaust port, look at the shape of the runner.

 

Yeah, but what are the measurements of the stock intake and exhaust ports? Does anyone know?

 

I'm sure someone knows.