so im leaving for charlotte NC on tues to go to a big ol ******* swap meet and to go to old junkyards. i want to get heads and a cam and lifter set for my maro. i have no clue what i need. the previous owner said he swapped in a 350 TBI. i dunno for sure if it is because i cant make out the casting numbers. any help will be greatly appreciated.

 

well i wouldnt just go grabbing heads and cam for a 350 cause if you have a 305 you will be very sorry and i mean very sorry as in slower than the 305 type deal... so you need to check the casting numbers... they are all hard to make out you really just have to see the last few and check that against mortec.com

 

There a casting number on the drivers side of the bellhousing flange, right behind the drivers side head. Get the last 3 digits of that number and post it here, we can tell you what you have.

 

Head casting #'s (last 3 digits) that are worth looking for:

083 (350 TPI)

113 (Vette aluminum TPI '86-1/2 & up)

081 (305 TPI)

 

all i can make out is 50LG and L61

 

so im guessing its a 5.0 aka a 305 and i got the shaft.

 

Don't think you're the first.

If you're still looking for good 305 heads, 081 (direct bolt-on), 416 or 601 (would require modifying the center two intake mount bolt holes on each side).

 

if i choose the 416 or 601 i wouldnt have to modify them if i have a pre 86 manifold thought, right? what is a good cam for these heads? looking for a nice lopey idle....

 

If you go about modifing your 305 with your head in the sand all you will achieve is making a good running 305 into a poor running gas hog.
Don't expect more than a very modest power gain from swapping one stock low perf head for another.
The 416 or 601 or 081 heads are only going to make it into a road terror once you've fully ported them with larger valves. Consider them a starting point (diamond in the rough) to work from.
But would be a step in the right direction.
Any "lopey cam" will want better breathing heads and manifolds/headers exhaust, a increase in compression ratio, a rear gear swap and torque converter swap.
Its very easy to over cam a stock or near stock 305. The low end torque gets eaten up quickly with added duration and overlap. Unless you're going to change/upgrade everything else and can afford a significant gas mileage penalty, you best rethink the "lopey cam" idea. We won't even get into emissions test effects.
Keep the cam duration and overlap modest until or if/when you make the rest of the required changes to bring it all together. Such a cam will not have a very lopey idle.

 

heres what i got.

373 posi
700r4 with shift kit and corvette servo
looking to pick up a 2800 stall
Edelbrock performer intake
Edelbrock 600 cfm carb
hei vacuum advance dizzy
mallory FPR
700r4 lockup kit
8.8 mm accel wires
magnaflow 3" exhaust no cat and flowtech shorties.

and i think thats it. thats what i have RIGHT NOW. im looking to add to it and im leaving at 3AM eastern tuesday (today or tonight or however you want to look at it).

 

I would look for a "113" corvette L98 aluminum head or a "081" 305 TPI head. Or maybe a set of "062" Vortec heads.

 

and port and polish them or bolt em on?

 

Other than some valvetrain mods you can bolt the vortecs on.
I would port the other castings If I wanted big power.
The 081's would need larger 1.94" valves. Consider these heads a starting point.

 

The first two are not a bad idea, but don't use the Vortecs on a 305. Your compression ratio with drop through the floor, since you would be going from 58cc chambers to 65cc chambers. On a small-bore motor like the 305, that makes much more of a difference than on a bi-bore motor like the 350.

Stick with the aluminum 113 or iron 416/601/081 heads, and you'll do well.

 

Got to disagree with Ya Adam. Even thou the cr will be a little lower, the airflow and chamber improvement will more than offset that. You'll end up with much more power.

You can mill off .040" from the vortecs and use a .015" head gasket and get all the cr you need on a 305.
I would not pass over a good set of vortecs for a reasonable price. Even with the mods+vortec manifold nessessary to run them, they are well worth it.
Just another very good way to skin the cat.

 

I don't know about that.. the Corvette heads will set the CR at 9.5:1 with a .039 gasket and flat top pistons. The 64cc Vortecs would be at 8.8:1.

The small bore of the 305 would also offset all the extra flow potential of the Vortec heads - which is why the 5.0 Vortec used different heads than the 5.7 Vortec in the first place.

I still stand by what I said - use the Corvette heads or some other 305 head.

 

Actually best of all would be a ported pair of 059 Vortec 305 castings. Even with my mild cam (Crane 260H), they easily pull 5,000 rpm.

This is a 5,800 lbs G20 Conversion van with 3.08 gears and the stock converter, with a little 305 in it. Ported 059s, Crane 260H10 cam, 9:1 compression, Edelbrock Performer intake, Stock TBI unit, stock cast-iron exhaust manifolds, and stock exhaust.

http://youtube.com/watch?v=Tvay9zOW6hE





https://www.thirdgen.org/forums/tbi/...tec-310-a.html

 

The World 305 heads I had on the 305 for 4 years turned out to have 64cc chambers (never did hear back from World with an explanation for that). They still ran a lot better than the stock LG4, even though the compression was down (also did cam and headers/exhaust when the heads went on the LG4, and the '86 LG4's got flat top pistons). Ditto with the Vortecs - yes, the 64cc chambers will lower compression, but the improved flow and chamber will more than make up for the compression loss.

As for Vette aluminum heads on a 305; yes, they're 58cc, but the "effective" compression will be the same as using iron 64cc heads. Remember, those heads went on 350's that used 64cc chambers when the heads were iron. Aluminum loses more heat through the material, so you need to raise compression to restore the lost energy (remember: heat = energy = power). When heat is lost, pinging isn't a problem with the increased static CR. So, 58cc Al = 64cc Fe.

Shrouding of the valves by the small 305 bore is a red herring - yes, it reduces power vs. a 4" bore, all other things being equal; but the larger valves and porting will still produce better flow for a 305 than smaller valves and no porting.