502 efi upgrade
 

IM upgrading my 454 330 hp engines in my 30 scarab panther to a pair of 1998 502 Mag 415 hp efi's.
I bought a pair of them and one has a broken rod and crank .After dissassembling the damaged one i decided to get a new rotating assembly (Scat) with all forged parts as that is stock in these.(Yes i knew one engine needed repairs before buying,lol)
My question is if im replacing the rotating assembly what can i do for mild power improvements without going crazy on the other engine too.
My thoughts were a camshaft upgrade maybe just to gain a few ponies, without the extreme expense(both engines of course)
If i upgrade the cams how does it affect the efi system?
Does the efi system need to be recalibrated , and how can that be done ?
Also what Pitch props would i expect to use?
With the 330 hp engines im running 60MPH @ 4850 RPM with 21 Mirage plus's which is higher than the 4600 Rpm i should have.
I figure a set of 25P mirage + props would be best but im not sure?
Thanx Ralph:ernaehrung004:

Did one. Scarab Panther, bravo drives, 502 MPI turned into 500HP MPI. ended up I think with 25 hydromotive QIV @ 81 MPH. Not too hard to change engine. Yes you have to remap the computer.

If you put bigger cams in,exhaust etc you might want to bore out the throttle bodys,its worth about 10 hp. I have a source for having it done,pm me if interested,Smitty

If anyone is looking a 502 to play with I got one that needs a home. 502 carb 123 hours. PM me you are interested.

jimg
Where did you get the computer remapped and what is it worth?Any idea what cam you used?What exhaust ?Thinking about Emi Thunders due to cost since true headers are extremely expensive for two engines.Are Emi's good enough?
Looking at Comp cams 01-419-8 / 114 lobe sep , 224/236 .510/.520 lift since they say no computer remapping required.
Thanx Ralph

Smitty,

When you bore the throttle body, do you change the flaps that in it??? where do you find these??

Harry

The butterflys are custom made in a larger diameter to match the bored out throttle body,it was worth about 10 hp/ft lbs of tq acrossed the board running my 540 N/A on the dyno,Smitty

If you change cams and exhaust, you MUST get the ecm remapped. It controls the fuel curve. Witout a remap, you will most likely lean out and burn holes in pistons. If you change to cam that says no remap is needed, then it is unlikely it give any more hp.

I have the EMI thunder exhaust on my 502 & I think that they would be fine for your modification plans. They will flow alittle better & are way lighter than the stock exhaust.

If you are doing so little in mods that it doesn't require an ECM remap, then why spend the $$$ for such a small gain????

Exhaust is a good purchase if you are going to do future HP mods, but it does little by itself.