It's still a porker of a van with a 2.75 rear gear, so maybe I'll just spin up some dirt for you- I haven't gotten it to just break loose on pavement yet.

 

just currious about how much did this cost? i bent a c rod and and am thinking about just fixing it and running it till it dies or since i have it out build it up. i would like to do something like this than rather get rid of the truck.

 

I actually haven't kept proper track of what I've spent, but I think it's in the $800 range. If I had to pay for my labor, it would have been in the $1200-$1300 range.

I have to say, though, it's well worth it. This thing has so much more power than before it's just wild. It's driveable, too, instead of being peaky like my old F250. I'm not sure if people closer to sea level would have as much success with this sort of build, but up here I can still run some pretty aggressive timing and not get pinging. My wife put about 110 miles on it today and actually enjoyed it too.

 

so just to get it clear what did you all do?
-just pistons(360 pistons and they cleared fine i read.) and rods and what brand pistons did you use?
-did you do cam too? it looks like you did
-how much exactyly did you bore it over? .50 over bore?

i got a 93 4.9l and i dont know if this would do good cause it is FI motor. i would like to try this cause i have the motor out and want to build it up or i got a freind looking ro a 5.0l with a 5spd trans for me right now but if i can do a build like you i might spens the money. i probably wont be doing any more mudding with the truck if i spen the money to get his done.
and hered is a picture of my #5 cyl that got chipped at the bottom from the rod bending after i hydrolocked the motor. actually the engine place i was going to have rebuild the motor had one sitting on the side some guy wanted them to sell so if my block wont do so i might buy that one and do it.

 

If your engine will clean up at the stock 360 bore (4.050) then go with that. My block was beyond cleaning up at 4.060, so I really rolled the dice had them take it to the .030 overbore for the 360, 4.080. I have not had a single issue with it, but I don't recommend it if you don't need to go that far.
In your case, though, I'd have them at least really check that hit area well, since it looks like a bit of a crack there. If it's not cracked, then just have them ignore that spot and tak it to 4.050 (if that will clean up the rest of the bores) and put it together with the 360 pistons. Your compression will be a hair higher, so make sure your EGR system is working. You might also have to set the base timing a little bit lower than the factory spec. Make sure you take Dremel and get rid of the sharp edge in the combustion chamber as that is a serious hot spot and will cause detonation.

 

yeah i have port ad polished the intake and exhaust and combustion chambers

 

Latest update: My wife took the van from here to LaGrande, OR yesterday without any issues. It got up to the "O" in normal on the temp gauge on long climbs in the upper 80s, but then dropped back down to the "N" or slightly below once the climb was over. I guess that confirms that yes, you can take a 300-6 80 over and run it just fine.

 

Right on Jared. The only thing stopping her now may be the GM trash ya kick up on the road plugging the intake.

 

I had an inquiry on this, I used pistons for a 75 F100 with a 360 and the 300 was a 78.
I ran the van for a while, but then we had another kid so I sold it off and got an Explorer. We left eastern ID a bit after that, but the van was still running around town.
I am picking up another EFI 300 soon mostly to get the trans and transfer case that's bolted to it, I may have to try a build like this again.

 

Gives me food for thought. My EFI combustion chambers are a bit small for the comp. ratio I want but the valves are pretty shrouded in the EFI head. Properly unshrouding them will cost quite a few cc's and may work out just right. The other pistons I am considering are like the ones you replace in the van motor. Shooting for mid 9's comp. ratio but 10 might not be all that bad at my elevation. Thanks for updating this thread.

 

Im doing a 300ci with 4.125" 302 pistons, Do you think I will have some problems? 80cc chamber, race cam,

 

If you are planning to fill the block up with Hard Block or similar you MAY have problems. If you are not planning to fill the water passages you WILL have problems.

 

Thanks for your response, and sorry about my english, so, I will have problems, do you say that block will colapse? its a bad block? I Make a new steel race crank, new steel crank bearings?, forged rod. Dou you have experience with this power problems?

 

The nominal wall thickness of a 300 block is about .160 - .170 in. That is if there is no core shift. So if you use a .125" over piston that only leaves about .10" cylinder wall left. At about 1000 psi there isn't much enough iron to last a very long time.

 

Hi, wich part of the block do you see will collapse with 4.125? and 1000 hp?

Cilinder liner?

Thanks a lot.