Thinking of building a motor...

[Crewwzin]

Its about time to rebuild the motor in sweeties truck. I want good low end torque but still be able to turn the tires if need be. Heres what Ive come up with so far with a little research.

freshened up 351W block bored .030 over
Eagle 393 crank
stock 351W rods
stock .030 over 302 pistons
GT-40 heads ported and polished
Ford EFI

What cam should I run? What do I need to do to the EFI to make it work with this engine? I'm sure of #24 injectors and a tune, but other than that, what else? This will be my first ever motor build and I wanna do it right. Thanks guys.

 

[EFI Guy]

If it were me I'd probably just run the stock Mustang cam. Stock Gt-40s don't gain any more flow after .510 lift anyway. Just make sure you upgrade the valve springs.

I would also go with a little more than 24's, and upgrade to a good slot MAF at the same time.

 

[Crewwzin]

What about a stock explorer cam? The only reason I ask is because I already have one.

 

[EFI Guy]

The Explorer cam is very mild and leaves a bit to be desired, but I have a buddy that runs the stock Explorer cam with 1.7 RR's and is pretty happy with it in a 351.

Edit: We are talking about a roller 351 block right?

 

[Crewwzin]

Its not a roller block at the moment, but I planned to build it as such. Or is that possible?

 

[EFI Guy]

I think that would require a small base circle custom cam and linked lifters. Seems like a lot of coin to me just to have it be a roller.

Unless you find a roller block for a decent price since you are doing a fresh build, I would just wait and see what the more experienced builders chime in and recommend in flat tappet flavor.

 

[rguest3]

Comp Cams makes some Retro Roller Cams to fit the earlier non-roller block.

The extra expense of a Roller Conversion is really not necessary for a mild street cam application.

Go with a Hydraulic Flat Tappet for the 351w. If going EFI make sure the lobe separation is at 112-114.

 

[Ranchtruck]

If you find a 94+ roller block it will already have the explorer cam in it and usually the cylinder walls are in such nice shape that you can just hone them.

 

[Crewwzin]

I've already got a good amount of these parts laying around including the 351w. I was trying to avoid buying a new block and all. I don't mind a flat tappet cam, but will it work with roller rockers? I'm pretty new to piecing a motor together from a pile of parts, so I'm trying to get it all straightened out before I dive off in it.

 

[rguest3]

Roller Rockers will work with all types of Cams.

"Roller Cams" have Roller Lifters.

Flat Tappet Cams have Hydraulic Lifters.

 

[Mountain Ram]

Roller Rockers will work with all types of Cams.

"Roller Cams" have Roller Lifters.

Flat Tappet Cams have Hydraulic Lifters.

Roller cams have roller lifters... Flat tappet cams use flat tappet lifters...

Generally speaking both would use hydraulic lifters for a street engine. Roller rockers can be used with both.

As to the rest of the build... You can get more from off the shelf aftermarket heads than the GT40s for a similar cost to a professional port and polish. If you are thinking of doing the port and polish yourself... Its a lot of work and small mistakes can trash a head quickly.

 

[needabronco]

Personally I think what you have would build a nice running engine. Don't worry about the roller cam/flat tappet cam debate! For what most of us do with our rigs that extra bit of horsepower (higher RPM) and very slight bit of efficiency won't be noticed.

For what you'd pay to rebuild a set of GT40 heads you honestly could not buy a set of nice aluminum heads! Now if you had to buy a set of heads and rebuild, then yes your in the same ball park.

 

[Crewwzin]

I don't necessarily have to port and polish the heads. I'm not trying to build a 600hp strip motor, just something with a little more juice than its got now. The stock crank needs to be turned, and for a $150 more, I can get the stroker crank. That just seemed logical to me.

 

[needabronco]

The stroker crank seems pretty logical at that point for sure! Porting is generally suited for higher RPM's than low end grunt, and there's a fine line in porting where you go too big and loose too much low end torque, I know I've done it.....

 

[Broncobowsher]

With cubes it needs to breath. You will need a good intake, since you are doing EFI, and EFI intake is needed. The 5.0 car upper with an adaptor to a truck lower is really only good for a stock 351. Anything more then that and it will be choked up. GT40/Lightening intakes are good, some aftermarket stuff exists as well. None of it cheap.

Next up the heads. While not my first choice, sounds like you already have the GT40 heads. You are about a third more displacment then a stock 302 a little extra flow will be good. But it isn't just flow, tumble and swirl also are factors. But realisticly the GT40 heads won't be considered too large, worst case just poorly ported. Another thing that is even harder, getting all the ports the same. Getting one to flow better or worse then the others gets into a poor running engine as the EFI can't really tune for just one cylinder doing different then the others.

So the cam. Roller is nice, but it looks like you have a non-roller block. Plenty of good flat tappet cams on the market. With the added displacment you will find the cam will run best in the lower end of the advertised RPM window. I always liked the generic RV cam sold by countless suppliers that has the .472 intake and .448 exhaust lift. Well proven cam that is just a little nicer then stock. Good idle with a hint that there is something a little stronger then stock. On a 351 with real good aluminum heads it makes power just off idle through 6000 RPM.

 

[nvrstuk]

Definitely stroke it. You will be amazed at the torque increase.

X2 what Broncobowsher said