How To Build a 289-302 One Horsepower Per Cubic Inch for $1,500

By: Alex Denysenko (MoneyMaker) Compiled by Don McDonald

If there is enough interest I can do a small block 289-302 one horsepower per cubic inch build up on this thread. I can put together a proven piece for $1500 or less so that any member can build their own. You must of course be able to do your own assembly and R&R labor. It ain't that hard gang.

After researching several machine shops in my area I will assume that these prices can be duplicated or bettered by most of the USA membership. This build up is based on a garden-variety 65-78 289 or 302 Windsor good condition donor engine core.

You will need to completely disassemble the engine. 
1) Degrease and cam bearing bare block with cam bearings $95
2) Bore .060 and finish hone $160
3) Micro polish crank shaft $30
4) Check connecting rods and fit piston pins $40
5) Valve job $130 6) Mill heads .030 $60
6) Machine heads for screw in studs $80
Total spent at machine shop $595

1) I opted for a PAW type of inexpensive rebuilder quality engine kit consisting of rings, bearings, oil pump, timing chain and gears, and a gasket set. These generally contain decent quality brands such as Michigan, Muskegeon, Detroit Gasket, Melling, etc. I priced mine through my normal wholesale supplier at $155. You may pay a bit more. 2) A set of Badger .060 11 to 1 pop up cast pistons from us at $150 3) Comp 270S cam, solid lifters, and valve springs $250 4) Steel shim head gaskets $40 5) Edelbrock Air gap or similar intake $220 6) A set of screw in rocker arm studs $20 7) A set of Headman 4 tube headers $90 Total of $925 in parts. Grand total of $1520 spent to get 300 horsepower at the flywheel. If you already have headers you are money ahead. The same with an intake. 351W heads would be a bonus and add about 20 to 25 HP stock. You will need a GOOD 600-750 max CFM carb. A 4100 series 1.12 Autolite is nice or a 700 CFM DP Holley is better. Anything in between is OK also except a Jimmy Carter POS carburetor. If that's all ya got then so be it! Whatever electronic ignition you have (like a FoMoCo Duraspark) is fine. This engine will make 300 HP@6000 RPM at the flywheel on a dyno guaranteed if assembled correctly. Does it sound familiar? Well it should, as it is basically a higher compression 289 HIPO. Add a bigger carb, tube headers, an efficient intake, more compression, more cam and you have got 25 to 30 more HP than the 271 easy. The best part is that it will last and take lots of abuse. These babies are very forgiving if the time is taken to assemble them right. Enjoy! Alex Answers Questions: Alex, .060 over ??? Is it worth taking a chance on the thin walls?? I have a few .030 over blocks that I was gonna use as core trade-ins on one that is bored .030....Is it safe to bore again? You can go .030 if you like. The .060 over bore being too thin is an old wives tale. We go .070 over on 289/302 blocks all of the time on our race motors. The pistons have valve reliefs. There is no economical similar piston for a 351 unfortunately. You will need a steady diet of 93 octane with careful timing adjustments. The 270S cam will allow the high compression. Loosing 2 full points will cost you 25 horsepower. Here in CA, we get stuck 91 octane, Which change would you make? Less timing? Or less compression? I always adjust the timing on street cars by the trial and test method. Keep advancing it until it pings then begin to retard it until it stops. It should still handle 32-34 degrees total on 91 octane. Are the steel shim head gaskets NECESSARY to handle the higher compression? Or, are they thinner to CAUSE higher compression? The SS gaskets are not mandatory. They are worth another 1/2 point in compression. They hold up very well and are cost effective. I don't like Fel-Pro head gaskets on SBF's and the Victors are $65 a piece. Any Chiltonís Mustang manual or Chiltonís motor manual is good. Better yet would be one of the Jim Osborn shop manuals available from M&M. Tom Monroe book is good also. Steve L. I always thought the Tom Monroe book, "How to Rebuild your small block Ford" was one of the best engine assembly books ever written. Alex, how do you fit in the variable of combustion chamber size? i.e., 289, 302, 302-4v heads, and 351 heads all have different combustion chamber volumes that will affect the compression. What heads (and/or combustion chamber volume) are those 11 to 1 Badger pistons designed to be used for? I assume the formula posted above is based on 11:1 compression for the HP, which is why I ask. I don't actually. The 48 cc heads with SS gaskets will garner closer to 12 to 1 and the 53's will be closer to 11 to 1 and the later model ones will be around 10 to 1. Remember that we are cutting the heads also. Smaller chamber heads will get closer to 320 HP. Regardless, the motors will make AT LEAST 300 HP. The 282 cam is a bit TOO radical for a daily driver as far as I'm concerned. Roller rockers are nice, but they just didn't fit into my budget. The sky is the limit as far as options are concerned. This is a tried and true combo with GUARANTEED results. NO BRAG, JUST FACT!