Diamond Dave

I have searched, searched and read every post I could find on this subject but there is nothing I found that is CURRENT or that applied to my exact situation. Old dead threads, no answers or updates, "just call this guy" replies, different setups etc.... I thought I would ask and see if anyone had any ACTUAL proven expereience with what I have going on and can point me in the right direction whatever that might be.

What I have learned in my searcing:


502 MPI intakes are lame and restricting
Silent Choice is limiting for cams
Mark Boos is great for programming ECM's
Tyler Crokett made a package years ago that was worth 100hp that I cannot find any info on and he seems to have vanished so far as I can tell...
Call Bob M.
Do not call Bob M.


Long story short, I have to rebuild one of my engines and it would be wise to do the other since it most likely has the same issues. Here is what I have:


1995 Gen V 502 MPI's 415hp w/ OE flat tappet hydraulic cams,
VST
MEFI 1
Stainless Marine exhausts w/ Silent Choice
All stock otherwise and 380 hrs.


One engine was taken apart (by a shop) and all the lifters/ rockers were scrambled and unmarked. I have been told I cannot reuse this valve train since it is a flat tappet cam because of the scrambliing. If this is true, since it all needs to be repalced anyways my HOPES are to duplicate or exceed a 500EFI engines performance. Specifically an upgraded roller cam/ lifters/ springs, rockers, etc. Maybe (?) some larger valves and head porting and of course ECM tuning. Anything more is out of the budget. I have made a few calls regarding this path:



Teague: cannot program my MEFI 1 and I would need to buy newer MEFI 3 systems/ wiring etc. Out of the question due to cost at this time.

CP performance recommended a EFI/ Silent choice compatible cam kit and they can have my MEFI 1 sent out (somewhere) and tuned: http://www.cpperformance.com/p-11632...ifter-kit.aspx (223/230 and .566/.575 at 114)

Precision Marine (Mark Boos) has done a tune for MEFI 1 which is silent choice compatible with a custom grind Comp cam he spec'd at 230/230 and .578/.578 at 114. I would need to source these cams and all the other parts (I have no idea how to spec) somewhere as well.



I am not a cam expert and I have no idea if these cams or machine work will come anywhere close to my goal of meeting or exceeding 500EFI performance so here are my questions:


1. Are either of these cams any good (the cam numbers are greek to me) and which one is a better choice? Or something completely different? (no Whipple or AFR comments please lol)
2. How much more power would I possibly be making with these cams and valvetrain?
3. Will larger valves be a good idea (they need replaced anyways) and will they alter any proven "package" ECM tuning that is already available?
4. Will porting or even cleanup porting of the heads (they need machined/ reworked and new guides etc. anyways) alter any proven "package" ECM tuning that is already available?
5. Are my goals unrealistic or am I better off just buying stock parts again and living with what these engines are since the gains would be minimal?
6. If the concensus is that this is a worthwhile upgrade, does anyone have any recommendations on PROVEN parts (springs, lifters, rockers, guides, seats, studs, pushrods, etc.) I would need for this job?


Sorry for being long winded but I'm learning as I go and as always I welcome any and all help!


Thanks in advance!!

Dave

buck35

Based on what I've read, and I have the exact same setup, 500hp is fairly easily attainable and the intake becomes a limiting factor after 550 or so. The scary part is the shop scrambling you're parts.
Now there was a thread discussing reusing mixed up parts some did some wouldn't.

Trash

I sent you a PM

Diamond Dave

Yes I am leery of reusing them if there is a chance it will fail I'd rather not risk it. The shop that tore it apart will not be reassembling it... lol.

Diamond Dave

Thanks!

Griff

You could just buy new lifters and install them with assembly lube and break them in just like a normal flat tappet cam install.
Inspect the pushrods and rocker arms prior to reinstalling.

Why was the engine taken apart to start with???

GLENAMY 242SS

iTrader: (1)

Inspect the cam first, heck a like replacement cam is only $250 new and GM HP lifters only $85 from Jegs if you want to do it in the cheap and stay stock.

SB

iTrader: (1)

TO answer first questions:

$90.97 set of 16 lifters from GMPP (GM Performance Parts):
http://www.summitracing.com/parts/na...ig-block-gen-v

$200 , or there abouts, for (16) rocker studs and GMPP adjustable rockers. The studs are so you can use the adjustable rockers.

Diamond Dave

Ah the story lol...

Ran aground which did some hull/ drive damage and sucked up debris for good measure, immediately overheated one engine and burned up its impeller. Limped back home after running out of gas twice (learned all about fuel gauge readings that day) and flushed and installed new impellor but now it had a miss. I checked plug and had water coming out of #2, I checked compression which was at 100-110 on that cylinder. Took it in to shop for hull and drive repairs and they took apart the engine to see if the overheat was caused by the original incident. They found a blown head gasket and evidence of previous water ingestion which they said was caused by OE exhaust (which I had replaced right after I bought boat with the Stainless Marine setup). They stripped the heads clean and took it down to the block to inspect the pistons, heads and all bearings. Turns out it was not covered since they said it had some signs of previous water intrusion. The head gasket was most likely on the verge of failing and the overheat sent it over the edge I'm guessing. The shop wanted 6k to replace all the valves, replace the main bearings, replace two pistons that had some scuffing and somewhat stiff wrist pins, all the rings and some light machine work to put it all back together. I felt I could get a full proper rebuild with upgrades even for way less money with a little legwork and some of my own labor so I here I am asking these silly questions... boating ugh... lol.

Diamond Dave

Well looks like that is definitely the cheapest option! I wasn't sure if the cam was something that needed replaced along with the lifters. Thanks for the link SB, any idea on what the adjustable rockers and studs I would need are specifically?

I also still want to explore the "upgrade" path before I make a final decision on which direction I want to pursue... Thanks for all the responses so far!