so i recently got and 1973 small block 318 i am very new to mopar and was wondering what to do to the 318 i have every thing but the pistons the guy that i got it off of droped one and cracked it, i also have 360 heads that i would like to put on i am thinking about putting kb 167 pistons (0.40 over) in it, stock crank, stock rods and a rad cam with a lot of lope because i am a stupid kid, and stock 360 heads and then some kind of single plane intake and then a 750 double pumper i am really on a tight budget. is all of this possible or unrealistic.
As an old fart, I may have learned a couple of things over the years.
What vehicle will this be installed into and what is your intended use. Sit back and have a real hard and honest talk to yourself on that.
You say you have most of the parts to put it back together but only 7 pistons. With your comment on "extremely tight budget" in mind, find the manufacturer of the pistons you have and purchase one replacement.
Being a youth you need to not go out of your way to find attention from those in uniforms. With that in mind, a quiet exhaust is required. That real lopey cam for street with power assist brakes even with a cannister is not optimal. You will be much better served with an optimized cam. By that a narrower LSA and less duration to keep overlap down will let you keep the vacuum assist brakes without issue. To select the cam LSA, either watch David Vizard's Powertec 10 videos. He has one on What the Cam Companies Still Get Wrong, and another that explains his 128 formula. This is also explained in his book How to Build Horsepower. Another excellent book is Porting and Flow Testing Cylinder Heads.
Uncle Tony of Uncle Tony's Garage presented a project to DV on 318 build using a 2V carb and looking to make over 300 HP. Charley Servidono has been porting the heads and intake for it. DV did a few videos on lightening and race prepping the connecting rods. This is applicable to street driving and will increase reliability at minimal cost but a bunch of time.
Another weight loss area is valves. The LA 360 valves are heavy due to a large part, large diameter valve stems. You could use Magnum valves with 1.88" intake valves and 5/16" stems. Another alternative is Chev LS valves. 1.9" intake and 1.55" or 1.625" exhaust. Because millions of these engines have been manufactured the parts are fairly inexpensive. You could go to a Pick'n Pull when they have a head sale and just pull the heads off a low mileage 5.3l or 6.0l and take the valves, springs, retainers and keepers from them. Sell the castings. These engines are easy on their valves, so the head machinist should be able to do a light touch up of the valves. These have 8mm stems. You get 5/16" bronze guides installed and honed to fit the valve stems.
For the cam LSA: 128 - (displacement of one cylinder ÷ ( int valve dia × 0.91)).
318 at 0.030" oversize is 3.94"
3.94 × 3.94 × .7854 × 3.31 = 40.36
Using the LS 1.9 Intake
1.9 × 0.91 = 1.729
40.36 ÷ 1.729 = 23.3. Just round to 23.
128 - 23 = 105° LSA indicated
It is probably hard to find a cam grinder that would grind someone they do not know a cam with that tight a LSA, especially if you are pushing for long duration. You should be able to get a cam ground on 106° to 108° LSA with 220° to 225° @0.050 lift. For lift you should be looking at 0.500" to 0.525". This would be similar to a Comp Cams Thumper cam and deliver the lope you desire. With 10:1 or 10.5:1 compression you should have a strong running engine.
For mostly street driving, IMHO, you will be better served with an Edelbrock Performer Airgap manifold. Stay away from the knockoffs as QC is showing up as problematic. For a carb I would choose an Edelbrock AVS2 650 or 750. If you want a Holley, the vacuum secondary 750 or a 650 will also work well. Double pumpers were designed as race carbs to give throttle response with long cams. The offset is that extra shot of fuel can be a detriment on the street. Yes it can be tuned to function properly, but you need to know what you are doing.
Think long and hard before doing anything and create a whole car plan. You build power into the engine you need to build power in the brakes (heavier duty) and suspension before you drop the razoo engine in. Once you get the plan finalized, with help from the geezers in the local car club, stick to it. Changing your mind half way through gets expensive quick.
Just a FYI, my neighbor's kid got his GDL about 01 Sept 2023. The G is graduated, so much of any infractions in the first year and they lose it for a while and have to go through the whole licensing procedure again. I see the truck he was driving parked at his mother's and had heard he had been stopped for speeding and seatbelt infractions. This leads me to think he is taking shank's pony about town. He is under the influence of his idiot cousins and their rectum attitudes. This has brought police interest and once they are watching they will not let much slide.
