Alrighty, the Lg4 is dying, has 150,000miles, burns blue on startup, eats oil, feels like it's going to explode at 3000rpm+ etc.

Anyway.

I have received a *FREE* (yes, free) 350ci out of a '72 Camaro [RS(?)], that came stock with a 2barrel. It smokes. The owner ditched it, built up a GM shortblock, sees my enthusiasm in building *stuff*, and says "here learn something, screw with this if you want power". Wow, I felt like I was just passed "the sword". Now I have a running 350ci in my posession.

I want to xfer some parts from the 305, such as the Performer intake, the Qjet, and the Edelbrock TES headers (305 style, ugh). But, I will ditch any and all of them if performance commands it.

What I want is, a motor that will pull HARD mid range, like 3000-4000RPM peak torque with like a 5000-5500 RPM peak HP. Holy sh*t is that a very broad garbage statement.

I have a decent sized budget, but cheap is good, as a trip to Europe backpacking takes precedence over speed.

I was thinking of going the Vortec route, but then I would be buying manifolds.

Or, I could get a decent set of worked junker heads as I want a lower RPM band than most nutcases on this board.

Another neighbour owns an engine machining joint, and quoted me a decent combo, but decided on a re-ground dupe of the 350hp-327ci, which he says works. But come-on!, comp.cams has come light years.

I'm rambling. What would you guys do, given say, $2500 (us) to blow? I am capable of long block assembly, sorta, but have never dove into the bottom end, and will not even attempt it. (With my own stuff that is, heheh)

One final note, gas prices in Canada is ridiculous, and the difference from 87octane to 92octane is considerable, but if you wanna play you gotta pay. =)

Thanks for any and all opinions. Building a shi*ty mismatched combo is not on my priority list, and I need your help.

Hype
1983 Pontiac Trans AM.

 

Hype,

That engine was rated at 145 HP @ 3,600 RPM, 250 ft/lb @ 2,200 RPM (pretty low RPM torque peak). It has a paltry 8.5:1 compression ratio, cast everything, and probably two-bolt main bearing caps.

One of the most important parts of a good build is planning. Your first acquisition should be an engine stand. Clean the engine and start disassembling. Mark all the components for location. Get I.D. or casting numbers from the case, heads, crankshaft, camshaft, distributor, etc. Do a little research to see what you have before you go to purchase all new components. Since the donated 350 is apparently worn, you'll likely be investing some cash in machining, new pistons, rings, gaskets, a timing set, and bearings.

If you are planning to increase compression, do it with the pistons instead of the heads, since you'll likely never change the pistons again. You can always reduce compression with the chambers, or even increase a bit with milling.

I would also suggest a new oil pump, core plug kit, and at least three four-bolt main bearing caps for the center journals if the case is a two-bolt design. Since you'll probably be align boring the crankshaft main journals anyway, this is the best time to convert to four-bolt caps. Drill and tap for the extra bolts, then have the entire assembly bored straight. If you are uncomfortable with assembling and balancing the "bottom end", you can farm out most if not all of that labor for a price.

Do a little more research and determine what cam profile will work for you. If the decision includes roller lifters, you might want to know that before the machining takes place.

Determine if the head flows are suitable (or close to what you want), then decide if new heads are in order or porting the heads you have would be acceptable. If they happen to be 461 or 462 heads, a little porting and valve enlargement can make them flow pretty well for a stock casting and they will provide very good torque at the lower ranges.

Since your case was free, it may make more economic sense to use it rather than start with a new short block. If something internal is really screwed, you haven't lost anything but your time. If you have to get a better crank, a complete lower end kit with pistons, con rods, rings, bearings, steel crank, gaskets, timing set, camshaft, lifters, and oil pump can be had for less than $700.00. For less than $1,200.00 in parts and machining, you could have a complete pseudo 4-bolt main steel crank SBC minus the heads. The rest of your budget could be spent on modifying the heads or purchasing aftermarket heads to suit your needs, and then go packing off in the Alps. Considering that your neighbor has access to some equipment for machining, you might even do a little better than that on labor costs.

If you really don't want to get into the bottom end on your own, you might be better off spending more cash on a short block and passing up a valuable learning experience.

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Later,
Vader
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"Make Me Bad"
Adobe Acrobat Reader 4.0

 

OK we'll create a truly "budget" buildup around the parts at hand.

IMHO the stock bottom end should be fine. I would not mess with the mains in the block, or a steel crank, or any other of that type of stuff; the stock 2-bolt setup is good for somewhere near 450 HP as long as it's all below 6000 RPM, which seems to match a "budget" build as you describe. With that in mind, I'd regrind that crank if it hasn't been abused, have new ARP rod bolts put in (one of the places it doesn't pay to ecenemize) and have them reconditioned. The hypereutectic pistons should be fine, with moly rings, which I would file-fit to about .028" end-gap with those pistons. I would recommend flat-tops, which should give you about 9¼:1 CR, which will work fine on regular gas given the right head treatment.

The heads on that motor (882?) are crap, as far as high HP (HP = flow), so there's no point in even trying go the extreme flow route with them. But they can be made to produce excellent mid-range torque, up to, say, 4500 RPM or so. So That will be the plan I'd suggest: a high-torque, mild cam, low-CR setup.

Do a mild port job on the heads: relieve the bowls right behind the valves, and shape the guide bosses into airfoils. Don't try to cut them down too far, just smooth them and streamline them. You can do that yourself with a Standard Abrasives kit and a drill. Lightly plish the exhaust ports. Do as little as possible to the intakes; for instance, don't bother with gasket-matching. Leave the surface mostly rough. Get rid of any casting flash or parting lines in the ports. Polish the chambers lightly, again, removing absolutely as little metal as possible. After they have been planed, should that be necessary, round off the edges of the chambers so there are no sharp edges in the cylinders.

I would not put that "141" cam in my worst enemy's car. It has been a joke for the last 25 years. If there is any one place to spend extra money, it would be to put a roller cam in this. A Comp XR264 would be about perfect. Otherwise, use their XE262H. Use their 1416 1.6 rockers in either case; stock ones have highly inconsistent ratios, so that alone is good reason for spending the $200 for the roller-tips. Get the "Louis tool" from Comp, and elongate the pushrod slots in the heads, that's something else you can do yourself. Put new valve springs on it: Comp 981s should be fine and will require no further machine work.

Use a standard M55 oil pump, & put the Mr. Gasket high-pressure spring in it. DO NOT use a HV pump, it is totally unnecessary.

I would turf the Q-jet and computerized ditributor if at all possible. With that many miles on it, that Q-Jet is largely used up: worn throttle shafts, leaking plugs, etc. I would recommend a Holley 6210 (650 CFM spreadbore mech sec) and a Perf Dist DUI distributor. You can ditch the computer at that point except if you have an auto in which case you would have to install a switch or something to work the lockup clutch.

With this combo you should have well in excess of 300 HP at the crank, and over 350 ft-lbs. of torque. You will absolutely have traction problems so save a hundred and a half bucks for LCAs and LCA mount lowering brackets.

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"So many Mustangs, so little time..."