Howdy just got a biger stocktrailer and need more poneys , i have an 87 F-150 4x4 with a HP351 4l carb. It has been sugested by a local mac. that i try a high rise manifold a biger carb and a biger exhaust system,maybe even a R V cam , my question is will all this help that much or is there anything else i need to try . I just need more power to pule the trailer with don't need a street racer, and this engein has a lot of moles on it (140 thousand) dosn't use any oil so i don't want to do anything that mite take away the relibality (ha)like if the R V cam would make me redo the valve springs i'm not sure i want to try them unless it would help that much. Also would headers help any and all help will be much app. thank you Mace

 

I would start with the exhaust system. A well tuned exhaust can gain you nearly 30 horses. But you have to be careful that you're not throwing away your torque. Doug Thorley tri-y (highly recommended) headers will gain your engine more breath and allow a little increase in torque to boot. But don't stop there, change your cats to hi-flows, and go to a true dual exhaust with a low restriction muffler like Flowmaster. Now that you've opened your exhaust, look at opening the intake. A high rise manifold will buy you a few ponies and some more torque, but I believe you would gain more if you took your stock manifold off, port matched it to the heads and gaskets, and polished the chambers in the intake and heads. An RV cam will certainly buy you some more torque and a few ponies and I doubt that it would be radical enouth to affect the cam or lifters. However, they are tough to install. Make sure that you increase your jetting in the carb if you open up the exhaust. Everything needs to work together to get you pulling those heavier loads.

Good luck,

Slik

 

Oh, another improvement would be an MSD ignition with adjustable timing. The adjustable timing will allow you to retard or advance your timing up to 15 degrees on the fly from your seat. This could give you some temporary torque for towing (retard timing) and still give you the HP for the "drag strip" (advance).

Slik

 

Sliks' are man!

I think factory ratings for the 351ho were like 195hp and 330ft/lbs or something. Do you know whether the Holley 4180 is factory? Does it have a electric or manual choke?

 

its electric, and i think it has 210hp@4000, and 330ft/lb@2800

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