[lilthumper]

Hi everyone. I just started a new prodject and was needing some advise. I have an 84 gt and it is mortorless at the moment. I can't decide if I should go back witha 302 or step to a 351w. Both will be stock bottom ended motors. I have both in short block form. They have got to be rebuilt. I am trying to sty on a budject. Then comes the question roller or flat tappet. Both blocks are non roller currently. Any opions will hep.

[EagleAutosports]

Since it's for racing, I'd go with the 351 block, and then rebuild it. It'll be more potential for power, and you can offset the added weight by getting fiberglass fenders and hood. I know that's probably out of the budget but maybe later on. You'd have more choices for cam if you went flat tappet, and cost less, but a roller will make a broader powerband and cause less wear on the engine. All you would need to get would be a roller conversion kit, the choice is up to you. If it were me, I'd go with a mechanical roller.

[acarter129]

I agree with Eagle, the 351 has a bit more potential. I have a flat tappet cam in my newest project. Eagle is also right that the power is more peaky with a flat tappet. I have found that a cheap alternative to the roller is to get rhoads lifters. I have them in my newest project. They open up the power band and help save some of the low end lost with high duration cams. They work and they are not expensive. Basically just pick your cam for what Rpm range you want up top, and the rhoads lifter will extend the lower range torque. Although a mechanical roller cam would be nice!!

[lilthumper]

thanks What do yall think about taking the 351 out to 393 being I do have to rebuild the engine any way and if I understand correctly it utlizes the stock 351 rods 302 pistons and an ofset ground crankshaft. Is this correct. The car will be street/strip

[acarter129]

I personally like the 351W in its stock stroke. The more you stroke it out, the further you are pushing the ratio between rod length and stroke length. Most ford engines have great rod to stroke ratios. Stroking an engine also changes the engines flow characteristics. The longer the stroke in comparison to the bore, the more it shifts the torque peak lower into the rpms. I personally like a bore to stroke ratio of approximately 1.1. The 3.85 in stroke of the 393 kit with a .030" over bore leaves you with a bore to stroke ratio of 1.0467 which isn't too bad. I would say go with personal preference.