POPODYNAMO

Hello i have a 305 HO and i would like to keep it so none of u guys come in her and say its a piece of S*** and im wasting my time..... So i was wanting to get some more HP out of it and i didnt know if i needed some of the stuff i have on there now so if anyone has any ideas please tell thanks

87_LG4

I spy with my little eye, something that begins with stock exhaust manifolds. If you have the L69 (as in HO) then they aren't as restrictive as lets say those of an LG4, but still a point of restriction that can be fixed without too much work and hassle. Some new headers would let the engine breathe easier, in turn freeing up some horses. Many people swear to the hooker 2055's as being the best small headers out there. I haven't tried them personally, but I have bought them, and will be installing them as soon as my engine is ready. I don't know how much work and/or money you want to put into this project, but porting the heads (or getting aftermarket ones) and maybe upgrading the cam might be something to consider. Perhaps 1.6 ratio rockers as well. I'm no expert, but this is what I hear a lot of others have done. Aside from that, if you still have the original dual intake air cleaner housing then that will provide colder (and therefor denser) air to flow through your engine than your open air filter is now. Denser air contains more oxygen per volume. (Slightly off topic: if you still have the dual air intake but don't want to use it, would you consider selling it? I'm in the market for one) Other than that you could buy a colder thermostat (and electric fan switch if applicable) to keep you engine cooler. But don't go lower than your climate will allow.
Hope that helps.

305sbc

iTrader: (3)

You can build a 305 basically the same exact way you'd build a 350.
In general, the parts to upgrade a 305 will be cheaper, with few exceptions like aftermarket pistons if you need them. A 305 won't require quite as much cylinder head port, valving, carburetion, fuel supply, camshaft duration, or exhaust primary diameter as a larger cubed engine would.
These "smaller" parts can be had cheaper, especially if bought used from someone who has upgraded.

The only kink in this plan is if you plan to upgrade to the larger engine in the future. You would then go through the process of selling of the smaller parts for the larger ones.

You need to go no higher than these numbers for a 305:
210*/220* int/exh duration for the camshaft
180 cc cylinder head port volume
600 CFM carburetor or TB size
1 5/8" exhaust header primary tube diameter
2.00"/1.55" valving in the cylinder heads (for 0.030" overbored 305 block)
72 gallon-per-hour fuel pump for carburetor with 3/8" fuel line.

Pretty much any aftermarket aluminum dual-plane intake manifold will work well on a 305, and they are cheap at swap-meets or ebay.

A set of 1.50" or 1.625" primary headers with matching Y-pipe and single 3" exhaust system will provide enough exhaust flow for a 305.