How much can a 5.2 block hold horse power wise? Will be running 16-20psi of boost. Any help would be wonderful thanks!

edit: if i posted this in the wrong place, please move it im sorry...

 

what are you planning on doing to the 5.2? i think the only big thing you may have to worry about is the limitation of the computer.

 

what have you done to prepare for more than one atmosphere of bost
which essentially can double your torque
o-ring the block
deck the block square
studs?
what gaskets?
forged pistons with ductile or stainless top ring?
got your quench around .030?
If you are towing or anything except drags do you have under piston oil squirters?
detonation sensor?
what compression?
what cam?
what fuel
are your pistons coated or at least polished?
how are you oiling your rods? pins?

 

Main goal is solid 11's in the 1/4. I ran 17.7 at 76mph all stock.

My plan so far is a complete 98 mpi swap to the magnum style heads and such. There eq heads, stainless valves, better springs, minor port work, bowl blending.

I am by far not new to the power making world, but mainly in cummins and diesels... I have built my sti to 500awhp so i am used to some cars.

I have read a crap ton of info on these old 318's and a few builds that did them all motor. But when does the block become the weakness? what psi, if any? Given that it has studs top and bottom, orings ect..

 

so are you going to swap to a magnum engine or are you going to just swap the heads?

as far a boost goes there is a guy on here with a fairly stock Dakota that is running about 7psi of boost on a 5.2 magnum.
https://dodgeforum.com/forum/2nd-gen...-5-2-dyno.html

 

Going to swap heads, intake, complete fuel system, wiring harness, pcm. Everything to make it work. I have a buddy here in CO that had a 318 on 16psi put down 460 uncorrected rwhp on mild mods.

So just trying to see what i can do with this early block. Which i think is stonger then the 98? I could be wrong tho.

 

i don't think the bottom end up a 98 would be any different than the bottom end of your 91 as far as strengths goes. stock heads and intake on the newer magnum engines are there major week points but if you swap those onto you 91 then it would be no better than the new engines. as far as swapping heads goes i think it would probably just be easier to swap in a magnum engine. otherwise i think you will have to get custom push rods and possibly figure out how oil the top end.

 

the heads from reading flow more then the stock 91 heads. These are not stock magnum heads tho... they have been worked over. I have seen swaps before just cant remember that well.

 

Im sure somebody will say something like "I have run that much power for X amount of years with no problems..." If thats the case, good for you, but I think the max you can get out of a 5.2 without having reliability issues is not much more than 400. Now, that being said... You mentioned that you are in CO. I happen to be a CO native up until a few months ago and I can tell you that If you are cranking out more than 425 rwhp out of a 5.2 in CO, you did somethin right. Its tough to get that many ponies at that altitude without runnin juice. That being said.... I have seen dyno sheets of a 600hp 5.2, so anything is possible.

 

Do you have a hyd roller cam?
You need AMC style oil through the lifter lifters if a conventional Hyd cam
or
Oil through the lifter hyd rollers
cam will be different NA vs Turbo vs blower vs nitrouis
7 lbs ok 10 is stretching it without mods I mentioned above
block is plenty strong,
The caps tend to walk, may need to be tightened up (peening next to cap sides with a chisel (or aftermarket caps)
With that then main studs and a quality line hone and if doing all that machine work then new caps if trying for 15 lbs.
WE reliably ran 50 lbs on a stock block AMC 199 6 cyl using only main straps and longer stock 1/2 inch head bolts (caps milled flat for the straps)
RPM ( especially with heavy pistons) is what kills rods, the rods especially with Direct connection (a real bargain- they are SPS) bolts or ARP
If needing to bore do no more than absolutely necessary
There is also the "cross the valley" oil line mod and some other oiling work to be done
Detonation will instantly grenade your motor so ignition/ boost curve is critical
I highly recommend reverse D cup pistons with 0.0 deck and no more than gasket thickness for Quench
I'd run the pistons with positive deck to get .025 quench