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More Power

CamVD

Jeremiah 29:11
Joined
Mar 19, 2012
Posts
82
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Location
Cutlerville, Michigan
Hey, I bought a 87 full size blazer back in october and just got done putting a 6 inch rough country lift on it. Its got a 305 under the hood with only 90k miles on it. I was just wondering if anybody had any good suggestions as to how i could boost the hp on it bc im kinda worried right now about making it up some dunes later this summer. Thanks for the help
 
Hey, I bought a 87 full size blazer back in october and just got done putting a 6 inch rough country lift on it. Its got a 305 under the hood with only 90k miles on it. I was just wondering if anybody had any good suggestions as to how i could boost the hp on it bc im kinda worried right now about making it up some dunes later this summer. Thanks for the help
Easy open hood
replace motor
replace hood
Done
 
Easier said then done. Plus im just looking for a few quick, cheap ways to increase hp.
The added power potential isn't worth the money and hassle IMO. The 350 stock motor is a complete turd the 305 has to be much worse.

Replacing the motor with a mildly built 350 in the long run will probably be much cheaper and more reliable.
 
With a 6" lift it probably either has bigger than stock tires or soon will. Gears will be your biggest bang for the buck. Going from 3.08 to 4.56 is about a 50% increase in torque. Getting that from the engine will cost more than the engine is worth. What gears are in it now?

Other than that, the cheap improvements are headers and exhaust, then a cam swap. But first go through the maintenance/free stuff like plugs, wires, cap, rotor and make sure the throttle linkage opens all the way.

Think hard before putting hi-po parts in a 305. It will never be a rocket. If you swap to a 350 external stuff like headers and intake will still fit.
 
In my 84 gears made a bigger difference than the 350 did.
 
Yeah, we need to know tire size, and gear ratios before we even start to worry about the engine.

Martin
 
Definately change the gears, it'll feel like you gained 100hp.

But beyond that since you have TBI and a budget i'd suggest doing an intake manifold, upgraded throttle body, headers, exhaust, and an adjustable fuel pressure regulator (do a search on that one). All of those can be switched to a bigger engine down the road if you so choose.

I ran a 305 for a long time and while the truck wasn't a rocket ship it still had plenty of get up and go with gears and minor bolt ons.
 
With a 6" lift it probably either has bigger than stock tires or soon will. Gears will be your biggest bang for the buck. Going from 3.08 to 4.56 is about a 50% increase in torque. Getting that from the engine will cost more than the engine is worth. What gears are in it now?

Other than that, the cheap improvements are headers and exhaust, then a cam swap. But first go through the maintenance/free stuff like plugs, wires, cap, rotor and make sure the throttle linkage opens all the way.

Think hard before putting hi-po parts in a 305. It will never be a rocket. If you swap to a 350 external stuff like headers and intake will still fit.

Took the words right out of my mouth! And welcome PO
from michigan :waytogo:
 
Gears, but if you have a 10blt frt and rear just look for a matching 4.10 set out of a 3/4ton. That would be a significant increase in strength and power, especially if your k5 came with 3.08 gears. :doah: Not to mention most likely the cheaper route, unless you know how to setup gears, but you probably wouldn't be asking how to add power to your 305 if that was the case.
 
if you jack the rear end up and rotate the tire one full turn and count how many times the driveshaft turns you will be able to tell what gears you have,,,example-if you turn the tire one full turn and the driveshaft rotates right at 3 turns you have 3.08,if it turns 3 3/4 turns you have 3.73,if it turns a little over 4 you have 4.11.......and so on and so on
 
But only if both tires are turning... If only one tire is off the ground, it will rotate twice as many times, so you have to divide by 2 as well. Or you can lift both tires and turn the driveshaft.

Somebody will surely suggest looking at the gears because it is the most reliable approach. When did you last change your gear oil anyway? You can either count the number of teeth on ring and pinion and divide or read the tooth counts stamped on the edge of the ring gear.
 
For the cheapest diy mods would be the tbi mods. Go look over on thirdgen.org and see what those guys are doing to their cars with the 305.
 
Yeah thanks everybody, im gonna put in new headers and an exhaust and when i get more money later on ill throw in a new set of 4.10s, unless i find a cheap set around. Right now ive got 3.08s, im hoping these things help enough.
 
Did you look at the tbi mods too? Throw an open air cleaner on top too. With a prefilter instaed of the whole housing
 

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