OK, I know I don't have a great performing angine and all that other stuff, so please don't try and school me on the 350 stuff. I know I could have gone with a 350 but where is the challenge in that. So, I have the engine and I have the intake a dual quad from edelbrock C26 with dual 500 cfm carbs. I am locked in with the intake and heads and block because I have the intake and I have the block and the heads are already at the machine shop. My machinist is going 30 over on the block and 10 over on the crank. I have forged 30 over pistons with flat tops and eyebrows for lack of a better term. I need to know what the best cam lifter push rod and roller rocker setup would be. This will be going in a streetrod of some sort if you didn't already know from the dual quad. It will pretty much be a show engine but I want it to run not just look good. I realize a 305 or a 312(bored 305) is never going to put out more than 350 hp even if that. I am looking for a solid 300 or even 275 out of this thing if I can get it from the stock heads 1.83/1.5 valves and only a 53cc. Does anyone have a solution that will make this possible. I am thinking I don't want to go roller tappet purely because of the price I want to stay around 250 for the cam and lifters. Again i am open to any suggestions to make this work if its even possible. I need an answer quick because I have to tell the machinist what springs to put in the heads. There is no turning back on the heads so that is not an option they have to stay. Any input would be very helpful, I am a novice engine builder and this is my first complete rebuild but I want it to be right. Thanks again and if you need any more info I will be happy to get it to you as fast as possible. Hope to see a lot of you at englishtown on Saturday (NO RAIN!!!) ( I plan on running a nitrous line maybe if that has any bearing on the cam)the intake has a rpm range of 1500-6500 and say that the max duration at .05 is 220 but I don't know how accurate this is. I need help.

 

Um, from your ID and engine size I get the impression this is not a Corvette related question, which would make it off topic. You know, there is an F body section on this forum. Perhaps your question would be better addressed there.

 

well they did make a C-3 with a 305 but if you guys don't want to help me out it's ok. I figured you guys would be the most knowledgable about all engines.

 

the bore is so small on the 305 that it restricts flow from any good heads is the main problem to me

 

If you plan on running nitrous all the time you race then select a camshaft dedicated to that. On the other hand, if you only plan to use it occasionally, I would pick a non-nitrous cam. For your app a hydraulic flat tappet would be fine. You will gain some power from a roller cam so if the money is there that would be the way to go. Stay with a hyd. cam and have your machinist put in the springs recommended by the manufacturer. If you have to put in a blanket spring that will cover you no matter what cam you end up with you will be safe with any spring that will handle .550 lift on the hyd cam. Just make sure that your cam and rocker assembly does not go past that when you build it. If you have any specific questions feel free to pm me and I can help you out further but this should get you started on the right track.

 

OK, I'll bite my tongue on your choice of a 305.

First, you have way too much carb. 1000 CFM on a 305 is going to make it very difficult to tune properly. It will fall flat on it's face when you get on it. Single 4bbl intakes are very cheap used, I'd seriously consider swapping it out. Since it's a show car, at the very least, you could just do something funky like disabling the secondaries on your carbs (just disconnect the secondary linkage).

I agree with comp, the small bore is your biggeest problem.

You can do some port matching / cleanup on the heads which may help some. Don't go nuts because you don't need big volume on a 305, just do a gasket match between the heads and intake and clean up any big casting burrs.

You'll need one of the more experienced engine builders to advise on cam selection. That's out of my territory. You could also try calling comp cams tech line. I agree that it's not worth going the roller lifter route on that motor.

A 305 is never going to be a screamer because of the small bore and relatively long stroke, so your best hope is to go for torque.

Good luck!

 

Don't know your crank but it should be ok to 8000 even if cast. Your weak spot will be rods and rod bolts. Spend some money here and on the crank if you can. At least radius the crank and try to nitride it if possible. It's easy to polish the crank yourself. I'd plan on 7200-7800 RPMs.

These engines need RPMs and compression ratio to make power. I think a roller cam would be great. If you want power you'll have to get some RPMs at a good CR. That means better stuff like double valve springs, good lifters, good cam, ARP bolts, maybe studs, good rods, at least hypereutectic pistons and the best head work you can get. Big unshrouded valves esp exhaust and match your ports. You can do some porting if you get some help by yourself. You can go double single or double barrels or cut the secondaries out which I've never done. Two 350's would be ok. You can cut the heads and deck on an angle to bump your CR but be sure to get a good machinist to do this. I'd say at least 11.5 to 1 for any serious power and more if you can pay for the fuel. Otherwise you just aren't going to make a whole lot here.

It's more of a challenge but a 350 is a better bet. You can use a 327 crank or 283 crank for a better combo but you still have to play the same RPM/CR game.

Good luck and let us know what happens.