351w guys...I need combos

[82 GT]

I am looking for some engine combinations that will give my 325-350hp from my 351w. My rpm range will be between 2500-6000 and I will be running a C-4 tranny in my '82GT
Is that possible with stock heads with port matching and some exhaust porting?

[mustangman65_79]

I don't see why not. Do u have a Bell housing for the c4 to a 351W? Other wise I'd be looking for a c6. I'm sure they did make c4 to 351. I just never find them.

[jim_howard_pdx]

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.

[gofastmercury]

I make 400HP, 400ft/lbs (dynoed) with my 351w. I use 70 ford castings, ported ext. big valve (1.94) but the intake port is stock, torker 2, 700 holley, cut trw popup pistons (10.6:1), stock rods and crank. The only thing fancy is the roller cam, which is way too big for this combo. I'm sure it would be faster with a much smaller one. It has .600 lift and 266@.050. It also had about 500 passes on it when I finnaly got it dynoed too. In short, I think 350HP would be very easy to get with out fancy (expensive) parts.

The c4 should work fine. The bell housing is the same for all 302/late 289.

[jim_howard_pdx]

I like your numbers, and your times match to your guestimates. I would say that the cam on its own is not overkill for your combination.

You are running a torquer II single plane and a holley 700 and you are right on for these pieces.

You are giving up an easy 35-45 horsepower by using such low compression. I use 13 to 13.5 compression on this type of race engine.

I would never use the ford heads because they are simply too compromised. My trick flow heads, out of the box flow more than a fully race ported ford head. I have ported mine to the 1262 felpro gastket which is just 1/4 inch shorter than the 428 CJ ports.

The 428 CJ heads were exact matches to the 427 low riser heads. They are designed to build excellent torque and hp from idle to 6,000 RPM. With some cleaver porting, we were running 428 CJ engines into the early 9's at 8,500 RPM with the Le Mans rods. What a ride. It spun the slicks to 100 mph with a solid spool. TORQUE CITY.

Interestingly enough, depending on your total overlap ( the cam timing when the intake and exhaust valve are both open ) the roller cam can act as if it is showing the engine high compression. What I mean here is that I like to run 11.5 to 1 compression with zero gap rings, a tight piston to bore clearance, and run a 600 lift cam at about 270 duration 235-245 duration at .50 with 36 degrees overlap. This super fills the cylinder at high RPM and the squeeze makes power like a 13 to 1 compression engine. You still need to run racing fuel or something with at least 104 octane.

You would be at early 11's with 12.5 to one compression with your cam. I would port the intakes to the 1262 felpro gasket. Leave an additional 1/16 inch of metal because these gaskets are soft and they get sucked into the port over time. The extra metal means the gasket will deform but not intrude into the air flow.

I have to replace my felpro gaskets EVERY 6 months. I start to suck oil or coolant, and I know I need to change these. Hopefully someone will make a high quality 1262 size gasket soon that will resist the problem I am having.

I have a race shop working with Mr Gasket ultraseal team right now to get this accomplished. Trick flow heads are everywhere, and the 1262 ports are similar to the world product Windsor heads or the Air Flow Research units.

By the way, I think shaving your throttle shafts on the carb, running double downleg hp boosters, and milling off your choke horn might get you a couple of tenths faster in the quarter mile. Is your car a double pumper or vacume secondaries?

[mustangman65_79]

[i]

The c4 should work fine. The bell housing is the same for all 302/late 289. [/B]

Hu, I was always told that u needed a diff bell housing with a 351w.

[82 GT]

No different bellhousing is needed. I used the same one that was behind a 5.0 and 5 speed with my 351w C4