WHOA
The ford heads are going to be your undoing. You need at least 1.94 or 1.97 intakes to hit 350 HP. When you calculate in the cost for the head porting, cause the stock ford exhaust port is simply CRAP, you are better off buying a set of good heads. I would choose either the World product iron Windsor or Windsor Jr heads. Either head might require some valve reliefs cut in your pistons. For that reason I bought the Trick Flow Twisted Wedge heads because you can run up to 500 lift and 290 advertised duration without notching your pistons.
Set this engine up for 9 to 1 compression if you use iron heads, and 10 to 1 if you use aluminum heads. I bought trw forged aluminum pistons. I use the good 71 W rods. The car takes 6k RPM all day long with NO PROBLEMS.
I am rebuilding the engine right now and I am planning on running zero gap rings. Should pick up 15 to 25 horsepower. It cuts blow by from 6% down to 1%. 6% of 351 cubic inches is 21 cubic inches of air and fuel blowing past the ring spacing. 1% is 3.5 cubic inches of air and fuel blowing past the rings. This is some serious power that need not be wasted.
If you port some stock ford heads. You will want to completely remove the hump in the exhaust passage. Do not try to enlarge the valve bowl, simply remove the flash and smooth it a bit. Blend the area around the valve guide. Tear drop the shape if you can. Buy a 1262 intake gasket set and scribe a mark in about 1/16 of an inch inward. Port to that and no further. Blend it back 1 inch toward the valve and be careful not to try to reshape the close radius. If you grind down too much you will be in the water jacket space. I just smooth that area out, any reductions are very slight on a street motor. Again you will want to run bigger valves. 1.94 and 1.60 would be excellent. Use stainless steel valves and bronze guides and a good set of springs to match your cam shaft.
I like a mild 3/4 race cam. I am using a grind that is 278 degrees on the intake and 288 on the exhaust. I am running 475 lift on the intake and 495 lift on the exhaust.
I run the Edelbrock RPM intake, and have it exactly port matched to my heads. I run the durospark trigger distributor. Set total advance to be NO MORE THAN 30-32 degrees. My valve guides got wasted by detonation because I ran the vacume advance to about 42 degrees. It was disastrous. Every one of my valves and guides is being replaced as we speak. The engine never pinged. It was detonating quietly as it drove about town.
I am running a holley 750, highly altered with annular front boosters and double downleg hp rear boosters. This car is great at idle and off idle. It runs just like a stock engine to 3500 RPM then it runs like a 428 CJ I **** YOU NOT! Most stock CJ 428's ran 14.2 to 14.4 second quarters. I am running 13.7 with my set up on 3.25 gears, a C-4 Tranny and 1400 to 1600 stall. This is a terrific street set up. With a Lentco AOD and 3.90 gears my computer program says my engine should run 12.25 ets at 106 to 109 mph. Now that would be exquisitely fun.
Please feel free to email me at
jim_howard_pdx@yahoo.com anytime. I am happy to tell you what has worked and what has not worked well. Cast aluminum pistons did not work well. I threw a rod at 5500 RPM. That was not my definition of excitement, but it was interesting watching my rod bounce along the roadway as all my oil gushed out the hole it made in my pan.
I would recommend you have a shop balance the reciprocating assembly. It is 175.00 or so, but it will make for a smoother and less abusive ride.
I know all the stroker tricks. So if you are willing to throw 1600 dollars toward the bottom end, I can get you 377 to 408 cubic inches. With good heads, a solid cam, and some nerves of steel you could be toying with 450 hp in no time...... All for less than 4 thousand dollars.
I would go the Lentco AOD route. If you already have an AOD, it will be easy to get a transmission shop to put in the solid main shaft and non locking torque converter. That will handle 600+ hp, shift 1,2,3 like the C4 plus give you acceptable highway RPM speeds even if using 3.7 to 4.3 drag gears. The build up will be similar in price to a good C4 and the AOD will be a better transmission, it is based off the FMX design which took high horsepower like the clevelands and laughed at the abuse.