I have lots of ideas that I think are good! LOL YMMV on the worth of these comments.....I re-read some of the original posts and worked through all the numbers, based on the 'daily driver' and 'limited budget': Just go for a simple performance project and work on keeping the torque decent and let the HP fall where it may, which is really where you were going originally.
- Stick with 318 closed chamber heads of some sort to maintain some CR for torque at lower end....easy to say, but I can't add anything to what has been said about the costs and other issues. The Magnum heads seem to be the best of the lot with limited mods. (I would not get caught up in using the swirl port 302's if the later heads did not crack as much.)
- I'd cc them to see what the chambers are, shave them and the intake maybe .020" to get the SCR up to around 9:1 with the Speedpros. If the budget does not allow, don't bother with the head shaving, it is not going to add all that much. Put in the larger valves if the budget allowed, and especially do a multi-angle valve job with a steep cut right below the valves to help the low end flow as much as you can. (We have 3 local machine shops with Serdi machines that can do that.) But you are going to have to take those ideas and go to your local machine shop and ask about the cost and make that trade-off.... it is a waste of time to try to predict that here.
- Get the highest compression height stock type cast or hypereutectic pistons and moly top rings. Sounds like you have researched that with SpeedPros. The only thing I can't find on the SpeedPros is their weight and pin weight to see if the engine will need to be re-balanced.
- Use the Felpro 1008 head gaskets
- Decking the block to get better CR and quench is something you need to price out for yourself at a local machine shop. Going for quench is a good thing to do, but adds another level of complexity and cost to the build. That is the first thing I would drop for a budget build. You are up near 9:1 true SCR and that will be purty good for a budget build SBM with no quench.
- Keep with stock rods and crank
- Dual plane intake, headers and 600 cfm 4 bbl carb
- Cam with a 256 or 262 duration; IMHO the 268 is on the cusp of not being good for the PB's; others may have better info on that. The 1.6 rocker ratio of the Magnum head will make these cams seem a little bigger. Maybe just 340 springs to keep the cost down there.... IF they fit on the Magnum heads, which I have never looked into.
- New oil pump and timing chain, bearings, damper, etc. I.e., spend money on good parts so it will assemble well and be reliable so you have a good daily driver.
This is not the fire breathing end-all build, just something basic, but your did say 'limited budget'. Even this realistically could run in the $2000-3000 range even with you assembling it. But it will be a good engine, and I think you will like it on the street. It is not really any different from your original plan or from anything else that has been said. It sounds more than anything like you need some help in comparing and contrasting and putting the costs and benefits in perspective.
BTW, do you think you could spend $1300 for a new set of heads? (That is a serious question....) That will put you in a different league with this engine. I am thinking you are more of a bolt-on-the-parts type of enthusiast, and something like the Indy LA-X heads from Hughes seem to be perfect for your situation. But, then again, to really use those heads to their potential, it starts departing from the simple daily driver with PB's, and there will be other expenses to get to that next level of performance. THAT is the problem with that next level of performance..... there usually is an associated significant step jump on costs to really get there. You need better head flow to get to the 300+ HP range, so that is the problem with getting obsessed with an HP number. I'll say it again.... you are going to enjoy the simpler build.
BTW, do you have the 318 engine now? What year?
