ok ive been searching, and searching, and searching and i still cannot find(get an idea) of what is a good head and cam selection for horsepower/torque with my lb9 motor. this car is my daily driver and i thought about swapping to 350 but i dunno if i have the time to perform the swap efficiently. so any help/comments/conclusions would be greatly appreciated.

 

Swapping in a 350 most likely wouldn't take any more time than swapping heads & cam in your car on the 305.

But, back to the original question:

305 head choices for TPI are basically your current 081 castings, or new World Products 305 S/R heads. You could talk about Vortecs, aluminum Vette (113), and other heads, but any of those options will involve "special considerations".

Your stock heads would need 1.94" intake valves (1.60" exhaust probably won't hurt, either), basic porting work, new valve springs to match the cam, and something to retain the rocker arm studs (either pin them, or have them replaced with screw-in studs). Fix 'em up, clean 'em up, slap them back on.

The correct World heads are p/n 042750-1 ( http://www.worldcastings.com/docs/05_cat_pg15.pdf ). They already have 1.94/1.50" valves, good springs, and screw-in rocker studs. They should also have the port/bowl clean-up done. They are pretty good castings, work well when cleaned up. Cost is about the same to slightly more than having the above work done to your stock heads. One advantage is you can get them ready while continuing to drive your car.

For a stock TPI, you probably don't want to go over something like a Comp XE262. If you are willing to get aftermarket runners, port the base & plenum, go with headers (you didn't mention exhaust), and maybe some PROM tuning, you could probably go with an XE268. Anything more and you're asking for trouble.

 

I'm with 5-7 on this. You could swap in a crate 350 in the same or less time than doing a head & cam swap on your 305.

Still, if you want to use the 305 you might try the World Heads along with a Crane 2032 cam. That XE268 is a pretty big cam for a street car, and I'll bet you'd have a hard time getting it to pass a smog inspection. You will want more fuel along with these so you will want to get an AFPR and bump the fuel presure up. Or go to bigger fuel injectors and burn a new PROM.

Crane Powermax 2032 452/465 214(270)/220(276) 112 deg., 1800 to 5800 RPM (2000 to 5500 RPM), P/N 104224 $280 @ summit.
Lift (1.52 rockers): 0.458"/0.471"
Lift (1.6 rockers): 0.482"/0.496"
Duration @ 50: 214/220
LSA: 112 degrees

 

Ditto the previous sentiments. It took me way too long to do my head/cam/timing set swap...but it was my first. I used the Worlds and I believe the 2031 (204/214,.429/.452) I got that one for the lobe separation (116 degrees) because the car is supercharged but that may not apply to you. One thing you might want to consider is whether or not you want to buy the Worlds as "assemblies." I did, and THE NIGHT BEFORE the swap was supposed to start I read a thread on these boards about someone with the big valve spring version of these heads breaking a spring!!. So, I opened up the Summit Catalogue and went to town. A week later, and further behind, I had the new springs and retainers, valve stem seals, etc. It took me some time to do this, but I'm happy I did. Please don't be mad at me for me throwing this curve ball at you but you deserve to have the most (best??) info to work with before you start. And, just for the record, I probably could've swapped three 350's into that engine bay in the time it took me to do the work. I work slowly, but should you decide to go this route you'll find yourself looking at that short block and saying to yourself, "Man, I really should've done the whole thing..." I suppose the grass is always greener. Good luck.

 

hey,
i was just wondering, ive heard people saying that with the small bore of the 305 you can only go so big with intake/exhaust valves because of shrowding? does anybody know what the largest size valves you can use w/o doing damage? particularly 2.02/1.60, will that work?

 

As far as I know, it's the 1.94 and 1.50 I/E combo. That's what World uses on its S/R Torquer heads but I don't know if that is the absolute limit. I would imagine that it is because it's more than likely that I already have a shrouding problem. I know there are people who regularly post on these boards that could give a much more definitive answer, though. I hope this helps.

 

Here is what a 2.02 /1.6 valve looks like in a 305 head .

 

In the heads designed for the smaller 305 bore, I think 1.94 is as big as you want to try to go on the intake, and that will require some unshrouding to take full advantage of the thing. I hear you can go as big as 1.6 on the exhaust. So you can have a 1.94/1.6 combination, and with some unshrouding, bowl work, porting, etc, they supposedly flow reasonably well.

Doesn't someone make an aftermarket aluminum head with the 1.94/1.5 combo, and a 58cc chamber? Seems like those would work well on a 305.

 

I posted this dyno info just to give you guys an idea of what you can get out of the 305 with decent heads.

https://www.thirdgen.org/techbb2/sho...hreadid=346050

The Vortec head swap looks like it's a good bang for the buck swap,,, and it's enough head that if you build a 350 later, they'll still supply good power. I'd think a Vortec TPI set up on a 305 would be a very strong running 305 combination.

The Vortec TPI base isn't cheap, but some on the boards have said that the stock TPI base can be matched up to the Vortec heads. I've thought about getting a set of Vortec gaskets to see for myself, but if it's doable, then that's the route I'd take. If not, Trick Flow has a set of 1.94/1.50 175cc - 56cc heads that I'd invest in before buying Vortecs and a new Vortec base - see link below

http://www.trickflow.com/product/che...3degree175.asp

 

D's89IrocZ: That is one heck of a picture!! I never would've believed it could've worked.

The only reason I didn't use the TrickFlow aluminum heads is because I bought the World's about eight months before the TFS ones came out. I believe that they have 58cc chambers and the large valves but I'm not sure.

The Vortecs would be perfect, but they don't have internal EGR provisions. The TPI bases, including the Vortec one, have external EGR tube provisions (for Corvettes) and I believe that SDPC2000.com has a kit that allows F-Bodies to use it, but it just seemed like too much trouble for me at the time. If emissions aren't a concern for you, then the Vortecs represent a fantastic deal. So much has been written about them that there's no point in me reiterating all of it. The point here is that there are a few options for the 305's, just not nearly as many as the 350+CI crowd has.

Of possible interest to anyone looking into this is that as of my last check of World's website, their information was not up to date. That has probably changed by now, but for the S/R Torquers this is significant as two of the machining procedures that World claims is necessary for the Torquer 305's were totally unnecessary on mine: they were already done!! The EGR passages were cast in and the perimeter valve cover bolt bosses were machined down. This was on the 042750-1 part number for '87 and later 305's. This could save a few bucks to anyone considering them. But, as I stated earlier, beware of the springs!! Do a search for information on the valve springs included in aftermarket manufacturers' head assemblies because the impression that I got is that they may not be the very best. It's just one more thing to look at when deciding.