Extra Power when Using Power Block

[Kelly N]

When all other things are the same on a John Deere A model, how much extra power should be gained when a POWER BLOCK is installed? Compression same, Head same, carburation and exhaust the same. I'm asking how much the extra cubes add from stock.

 

[buickanddeere]

What was the before displacement and what was the after displacement?
Is the head, valves, ports, manifolds, cam , carb and exhaust stock?
Lots of builders go wild on displacement and mechanical compression but don't support the extra airflow demands with a re-ground cam and port work.

 

[Kelly N]

it is now a 125 over with aluminum pistons it has an after market flat head with big valves and big ports it is not stroked. I was wondering how much extra the extra bore will give if the power block is bored 125 over also with the same compression as I have now. Basically I'm asking how much power did the power block add when they were used on stock tractors and this will give me an idea of how much it should gain by using one in my situation.

 

[Josh Blackburn]

In my opinion- 8-12 hp with set up your explaining. 62 more cubes with the extra 1/2 inch bore.

 

[buickanddeere]

You would be hard pressed to find the difference in HP between an engine with perfectly round and true stock bores. Vs the same engine with .125 bores.
If it cleans up with a 45 thou over bore . Stay there and save the 90 and 125 for the future.
There is missing HP if that cam if the old worn unit that was installed by the factory.

 

[[email protected]]

Original tsc adds can be found in the internet, & list the before/after hp. However, half the point. Of, &the results from, installing a power block was an increase in compression. They came with domed pistons, which were higher compression aoutside late B went from 5.4:1 to 6.9:1, & hp from 28-36. Bore was 4.69-5.0" you could also get 8:1 LP pistons for it.

 

[secret 77 puller]

the power block traded out for a stock block takes an A from 321 CID to 382 CID. now add some off set grind for a really good cheap puller in div 1.

 

[Rob Hartman]

I have a 1941 "A" with a stock bore Power Block, gas manifold, stock rebuilt head and stock cam that is"nt wore too bad. I bought the tractor stuck so I don"t know what a stock one will do on the dyno but mine right now like it sits will pull 60 h.p. I have 15/5-38"s on 16" pressed steel and I can pull 3-14"s in 4th gear. I"ve pulled 4-14"s in 2nd but I don"t have any weight on and it spins out. I"m looking for some 13.6-38"s or 12.4-38"s on 11"-13" rims because I have way to much rubber on the ground now. I have 2 sets of weights to add to it too.

 

[John Deere G Man]

http://www.jd2cylservice.com/

Good info on JD stuff . Look for the "aftermarket" file. It has pics, and info on all this stuff. Including dyno tests on tractors with and with out PB's .Also has JD bearing cross too. Just a nice simple site

 

[jd b puller]

If you add a powerblock to your currect setup, you"ll probably pick up 6-10HP.

By comparison, you could put a 9" crank, and cam in there for about the same money and pick up 20+ HP. Nice thing about stroke is it still looks stock but gives increased power at all RPM"s.