Maybe I'm missing something here. I have planned in finding an engine builder to at least get my 318 into a rowdy long block. I found a company near my work that builds engines, mostly ford, but some mopar too. After talking to him for an hour his thoughts were:
To get 350hp from a 318 you need 10:1 cr. He's also pushing for a roller cam and roller rockers. I'm unsure of what Pistons he had in mind. We also discussed porting and polishing my 273 920 casting heads. He claims with a cr of 9.5:1 and the valve train work I'll be about 320 hp.
Does this sound right? I guess I was under the impression it took less to get hp from a 318.
He's also saying for $5500 he will do all the needed block and head work, source the valve train parts, intake, water pump, and pistons, balance the assembly, and install the engine in the car to see it run. I'm still coming to terms with the price, I can't figure out if it's a decent deal or not. ThoughtS?
To me the price doesn't really sound high. Talking about replacing all the wear items, buying the new parts, converting to roller cam, buying roller rockers, replacing pistons, porting, and redoing the heads.
However. On such a complete deal, the question moves not to how much less you may want to get it done, but how much more you may want for your money. Not having to buy $800 worth of roller lifters and cams can put you money ahead to buy better heads. Having better heads can increase where your HP will end up. To me- you could do it for less, but probably right around there at his prices you could have a 390 Magnum running in the car at quite possibly 100 more HP- so adjusting what you're after could turn that from a good deal to a very good one.
That said, if you were to go cheaper, I'd obtain a good running 318 or 360 Magnum, convert it to run in the car however you want, and be happy with the 240-320HP depending on what your "stock" installation ends up being. It'll be a world of difference over the 920 head teen and that'll be all over the range.
Magnums are LAs. You can convert to carb by simply using LA components. The front cover, accessories, an LA-spec cam (there's long snout rollers too), mech fuel pump, distributor, an LA intake, all can be used in conversion to carb of a Magnum motor. That's not the only way, just a way that clarifies just how LA the Magnums are. They saw relaxed smog restrictions and had an easier time meeting them with fewer devices.
Well I guess I could always go the magnum route, but if he's right I suppose I should adjust my expectations
Yes. Those small port 318 parts are not very conducive to power. People use them as a band-aid for smog motors' compression but the flow isn't there. Even if you're only putting a few hundred in a motor there's better choices.
Or the better way like the new Hemi's or LS is to put really good flowing heads and smaller cam so you get power and drivability.
Smaller cam? They have pretty good sized rollers. Small compared to race motors, very large compared to what any A motor ever got. MPFI really tames them despite the cams being a bit large. They're just soft on the low end until they get up into their range. Relatively small bores, mid-sized valves, and long strokes.
The 340s and E58s had a powerband comparable to the lower of the LS and Hemi motors. The Magnums had powerbands more like the smog motors peaking around 1000 under any of those. Longer stroke means less RPM for the same HP. Less RPM for the same HP means you need less gear to hit your peak.
