glad i got one with the balancing shaft....

 

Because a 305 has small cylinders with valve shrouding. A 4.3 has 350 cylinder bores. Truthfully it is a 350 minus 2 cylinders. One of the magazines had a 500 hp 4.3 in october of 01 or 02.
I have not yet seen a 500 hp 305.

 

Man you have alot to learn. A properly modified GN motor can hand any properly modifed 305 its rear. That is a well designed V6 versus a poorly designed V8. The GN engine does run with the big boys, I have seen a video of Buick GN beating a viper. Granted the viper was stock, but still. That is a V6 beating a V10.

As for the 4.3 its been built to 500 hp, Show me a 500 hp 305. The closest I seen was a 475 hp version.

 

now that i think of it the 4.3 would definatly be a sweet setup with the typhoon ecm, modified intake, and a cetrifugal supercharger. That would really kick some *** out on the street if properly tuned, not to mention the look youll get when you show the other guy what beat him.

 

I would go with a MSD throttle body with progressive linkage, six accel injectors, Holley commander ECM, carb pressure box, edelbrock 4.3 carb intake, and a vortec or similar blower. People wouldn't know what hit them.
If I had a V6 this is the route I would go, just to have something different.

 

The whole V6 debate, in my opinion, depends on your goal. I have a 4.3 in my IROC because I had built it for my daughters Triumph TR7. Backed by a Tremec 5 speed, I never really saw the backend of any 5.0 when it was in the TR7. Unfortunately, the peanut rearend couldn't take the abuse and puked. I am currently in the middle of a new 350 build for my IROC and knew that the funds needed to build the V8 I wanted would force this project into a few months of waiting. In went the V6 because....it was there. I had to adapt motor mount adapters but it bolted right in after that...Tremec and all. I noticed an Edelbrock 4.3 Vortec manifold on EBAY and couldn't believe my eyes. I knew V6 Vortec heads were nearly a copy of the V8 Vortecs with a cylinder missing on each side. There is a pot of V6 Vortecs floating around. Picked mine up for $95 including shipping and they are at the head porters now for some bowl work and the same modifications to the guides as the V8 for cams over .470" lift. I will purchase the Edelbrock new very soon.

Quite frankly, I'm glad I made the swap. The car is loaded with Spohn and Global West suspension. With the 200 lbs off the front end, the sucker flat handles. If it were legal for the Prepared class of SCCA autocross, I would have a ringer! And even with the 4:10 rear end, I'm managing in the high 20's for gas mileage. Will it remain in the IROC....heck no but for someone who likes great handling cars and can't afford to pay the big dollars for gas, it's not a bad swap...especially for the 2.8 thirdgens.

 

kids

 

hmmm last time i checked valve shrouding did not occur on a 305 (with 1.94 intake valves) until a rediculously high lift number (.575 i think)

time to rethink this.........

 

You aren't limited to 1.94 valves on a 4.3. If a 305 didn't have problems with valve shrouding, we would be seeing 700-800hp 305s.

The little bit of displacement difference between a 350 and a 305 isn't enough to cause for a huge difference in HP numbers. Think about it. More people in Ford land use the 5.0 rather than the 351. Right now they are using 4.6 motors and getting much better numbers than most 305s.

 

Now your thinkin'. I actually thought the the Edelbrock (Weber) or Holley four barrel throttle body would be cool. Drilling the Edelbrock Vortec intake for six Accel injectors is an excellent plan. I'm not sure if you could seal the Vortec pressure box properly but if you could, the possibilities would be great. GM sells there version of the Bow Tie V6 block for serious HP attempts. How about a bulk head drilled into the back of the block at the lifter valley for a hidden direct port NOS shot underneath the the intake for extra insurance.

 

Dual power adders on a 4.3? LOL, better have a bowtie block for sure. People have home made pressure boxes, and I belive there are a few guys in the power adder forum with TBI units in a pressure box.

 

you warped my point i was trying to make

 

For the disbelievers...here it is. Dyno proven.

http://www.speedomotive.com/4.3%20ch...t%20master.htm

Again, I believe the V6 Vortecs and Edelbrock manifold could even be worth more power.
And for those with really deep pockets....
http://www.strokerkits.com/4_3_chevy_v6.htm

 

The point is a 4.3 is a well designed V6, while a 305 is a poorly designed V8. A well designed V6 has more potential than a poorly designed V8.
Now compare a 4.3 to a 350 and the 350 will win everytime. Compare a poorly designed V6 such as the 2.8 to a 305 and the 305 will win every time.
When things aren't equal though and displacement is close enough the better designed engine will win regardless of cylinders. Take a look at the early caddy V16s for proof of that.