gonna do the old 305-350 swap. Is this gonna be good for a weekend cruiser with an occasional run at the track? Rebuilt 350, crane energizer cam 218/218 .450/.450 ,performer intake, edelbrock performer 600 carb, and i got a set of good L98 heads for free. Will i need new springs and pushrods to be safe? Im still gonna use my T5. Should i keep my 3.23 rear or put in some 3.73s?

 

I wouldnt use that cam. I would go with something in a dual pattern setup. More duration and lift to the exhaust lobes. Maybe one of the Comp XE grinds. Buy the kit that comes with the right springs. New pushrods couldnt hurt, be sure to measure and make sure you have the right length. Do you have a good HEI distributor to go with the carb?

 

the jist of it looks ok. A few minor changes/suggestions should be made though.

The heads. Since they are free, they will probably be used. That being the case, I would run them to a shop and have them clean them up. They already have 1.94" intake valves, but having them cut to a 1.6" exhaust valve (they come with a 1.5") would not hurt any; it would be more benificial, if anything. Once you get them back, get yourself an electric die grinder (1/4" shank, not a dremel) and some carbide cutters and have at them! You can port them yourself, it's not that hard. Do a search for a guy named Sitting Bull. He has a great thread listed in his sig that gives a very good run down of whats all involved with the project. If you are worried about screwing up, talk to the machine shop. Ask them if they have a junk head you can practice on. I got an 882 casting for free. Only takes a little bit on both the intake and exhaust to get the general idea of how to control the die grinder. Remember, heads make the power. Another thing to consider, depending on what cam you choose, have them mill down the guide bosses for more clearance between them and the bottom of the retainer. At about .480" +/- is when clearance issues become a problem on most factory castings (of the the third gen era and previous). Another thing to think of is screw in studs and guide plates. I believe all iron L98s were self aligning rocker arms. By switching to Comp's retainers and locks, you are essentially putting on the equipment for non-self aligning, meaning guide plates are recommended. To do that, you would need screw in studs to hold them in place. But, that's not that bad. With screw ins you don't have to worry about pulling a stud during operation. Rocker arms are up to you. I would recommend at LEAST a set of Magnum roller tips. I recommend avoiding aluminum as they do not have the fatigue resistance strenght as steel.

The cam. Factory heads are notoriously "sluggish" on the exhaust ports. They leave a lot to be desired. Because of that, a dual patter grind is highly HIGHLY recommended. The Xe268h by Comp Cams is a great cam for a mild mannered 350. It would work with the 3.23 rear gears and wouldn't need anything crazy on the compression. Comp sells K-kits. These come with the cam, lifters, timing set, valve springs, retainers, locks, valve seals, and some assembly lube. For about $350 you get all of this. If you price it all up, it's a pretty good deal, considering you don't have to worry about matching it all up. It essentially comes with all you see in the picture here:

Summit lists it for $310. Yea, I would run new springs. It is always best to run new springs anyway. Anythings better than the factory POS's. They only have about 85 lbs of seat pressure from the factory and they can only get weaker from there. Seat pressure = resistance to valve float. So more is better, to a point. If you get guide plates, you will need a set of hardened pushrods to go with it. Summit sells these for about $35 or so.

The Performer intake is really nothing more than an emissions legal replacement. I would recommend a ZZ4 intake. It seems to be a bit better. I have one on my LG4 currently. Try looking in this sites classifieds, post a wanted ad, etc, try eBay maybe.

I don't know if I would trust this setup to a T-5 though. As-is, they are notoriosly weak. Perhaps there's a reason GM never put one behind the L98....at least not for full-time production...

What are the plans for the bottom end?

 

Im gonna throw the word "budget" in here. Im gonna use the Mallory High Output distributor and performer intake from my 305 just because i have them and they work. So since I have an L98 block and heads, why not use the L98 cam too? I hear that adds a good 50hp. That would leave me with enough money to have bigger valves put in the heads and i wouldnt have to machine them. I already have a set of sealed power 1.6 roller tip rockers i can throw in there to raise the lift to .430/.442. and i have new springs that are good to just under .500 lift. The tranny is getting rebuilt, and at most i will put 10k miles on this engine. Hows that sound?

 

Buy a different cam. Dual pattern cam...the 218/218 will not perform well on your motor..

 

What I list is about as budget-y as it gets, while still using an aftermarket cam and an overall engine design that makes power.

The L98 cam will make 50 more horsepower. 50 more over what? And more than likely, no it will not.