Building 496 from 454, cam advice
 

Engine is dying so mine as well pull the 454 and build it up. I'd love to get to 500hp. Already have 496 merc alum exhaust manifolds, 188 GM rect heads (which I believe are same as 502 500 hp heads correct?). Thinking of going to single plane intake, 60 over flat-tops, stroker crank, rods (all forged stuff of course)roller lifters, rockers, cam. Any cam suggestions?

I just got 520 out of mine with dual plane and oval port heads. Flat tappet cam.

You should be able to get way more than that with a roller.

The oval port heads are going to be better for you though. The single plane will be nice.

Did you mean to say the rect heads will be better? Im trying to work with what I already have, so i'm going to try to work with the rect heads. trying to mimic closely the 500hp 502 best I can.

The squatres are only better with more displacement or cams. In marine engines the big chevy or Merlin ovals are etter except for maybe that last few rpms up close to 6000. Ask around on the board. Those ovals are better overall in the middle and down low, and they don't cost enough horsepower up top to make a difference.

If you are going with the squares, you might want to stay with a dual plane to help in the mid range. 500hp is not a very hard number to reach with that engine, but remember you are going to get way better torque numbers with that 4.25 crank then you are with that 4" crank and that is what you want.

Its a heavy boat for single motor, so down low and mid range is very important. In fact I will rarely run over 45 mph, I just like to know I can hit 60-65 mph if I want to. Want to be able to cruise at 40mph with 1/2 tank gas, 4 people and gear aboard effortlessly. I currently have a GM dual plane for rect heads so I might stay with that and see how it runs. Holley 800 will be in order as well.

I just dynoed my 496 my a 750 and a 850. There was no change when we went to the 850. More carb than the engine needs only wastes money.

Cam suggestions:
1) Bob Manderra (RMBuilder)
2) Crane doesn't make it anymore but if you can find a Crane '731' cam, buy it.
3) Crower makes nearly the exact same cam as the 731. It's part number 01404LM, Valve lift is IN .585/ EX .612. Duration at .050 is IN 236/ EX 245. Lobe separation is 110 degrees instead of the 731 which is 112 degrees LSA.

You'll need a better intake, stock ones are garbage. get an Edelbrock Performer RPM Air Gap or a Victor Jnr if you have to have a single plane, most Dart, World, Brodix and Merlin intakes will be just too much for the RPM you're looking at. If you already have the rect port heads don't worry, they'll still work but you'll deffinately need the best intake to control the flow.

I'd recommend a Holley 750DP Marine carb but be prepared to swap jets until you can get from 2000-4000rpm without coughing of spluttering if you hit it.

What ignition are you planning on running? Avoid MSD 6M in my opinion.

Good luck, let us know if you get stuck!
John :drink:

I was just planning on reusing the stock Thunderbolt ign with MSD coil. Thanks for the cam suggestion.

:flag: I'M JUST SAYING IF YOU ARE GOING TO GO FASTER YOU NEED TO BUMP UP THE COMPRESSION TO 10:1 YOU WILL HAVE TO RUN 91 OCTANE ALL THE TIME BUT ITS WORTH IT CAM LIFT SHOULD BE IN THE 632 RANGE AND DURATION NO MORE THAN 252 OR 262 WITH A SINGLE PLANE DART WITH A 1050 DOMINATOR IF ITS IN THE BUDGET AND GET A BETTER IGNITION SUMMIT RACEING 1-800-230-3030 HAS A COMPLETE STRIP AND STREET UNIT WITH COIL BOX AND DISTRIBUTOR FOR $326.95 AND YOU SHOULD GET A LITTLE OVER 600HP. TEAGUE MARINE SELLS THE CAM ITS CALLED A STAGE 3HYDRULIC ROLLER 661-295-7000 TALK TO ERIC TELL HIM ERIC SENT CHA FROM 310 EXPRESS

That's fine. SRP or JE makes a 9.5:1 piston. That is plenty of comp to get you over 500HP with a decent roller cam. It will be higher if RMBUILDER designs it for you.

Merc tbIV ignition is Ok also, It is better since you can get parts at local stores later on if you need them on a weekend etc.

Have some port work done to the exhaust side of those heads if you have some extra cash.

You'll be fine with that. Later on in life if yo uwant to go bigger, you can use the cranks and rods in an aftermarket block and a new set of pistons and go 540-565CI.

Use those old heads and still make over 600HP.

WHY ARE YOU YELLING AT US???

Just Kidding! :lolhit:

:drink:

Ghostrider,

Why should we avoid the MSD 6M?? Juts curious, (my boat already had it when i bought it)...

Thanks,
Julian

The 088's are the HP500 heads, unless they had two versions of the castings.

There are several casting numbers for the square port head. I acn't remmebr all of them, but 188 is one also.

I did a search on here (it's my bible!) when I was looking for ignitions for mine. Of all the reviews I read, the MSD 6M had a common theme: They stopped working at an very inconvientient time / place. Several members on here have gone through multiple boxes, so far as I can tell, MSD tech support only ever tells people the box stopped working because of a 'poor ground.' I'd prefer not to get stuck so I didn't use the 6M. Crane no longer makes their HI6M so I went with what I thought would survive better.

It's just my opinion, as I've never had an MSD Marine Ignition before, but all the issues noted on this forum can't be wrong can they?

I'm not against MSD, I run an MSD HVC ign now, if it can survive NASCAR, it'll probably last for me! (I Hope!) :drink:

It's not always the ground, but that is the easiest way to describe it. If the MSD box is wired into a circuit where there is an intermitent drain, like a radio with a big amp, trim switches, tabs, lights. Just about anything, then it varies the voltage in the box causing it to weaken and then fail. They rarely fail if they are connected straight to the battery or a dedicated circuit, also there is a part that MSD makes, it is a resistor that goes in line, that aids with varying voltage issues also.

I have some really old MSD boxes, have to have run for 5 or 6 years that I took off some engines. They were still working perfect when I took them off.

Really, the TBIV is a fine system and is still reliable. Rememebr that Merc used them over 500HP. Why can't we??

It's actually a capacitor :D

yep, that's it.
http://www.msdignition.com/Products/...,_26_Kufd.aspx

26000 pico farad capacitor (26Kufd)

I spoke with Eric at TeagueMarine and he recommended the Stage 2 cam. I'm going to use 9.5:1 pistons, Dart single plane, Holley 800. Hey Ghostrider, if I come down to Sydney in a few months, you going to take me for a ride in the Stinger...I owned a 222 for 15 yrs before my current boat (wish I still owned it)

I have built several 496's and I have two in the works now for my new boat.
Just my advise, 110 center line you might have problems with reversion. I run 9.5 compression with aluminum heads, if you are running iron you better have good gas. I run 91 and have not had a problem.
I would still advise using RMBUILDER I buy all my cams and lifters from him. WELL worth the $$$$

Good luck

496
 

Ok so I got a 454 stroked to 496, Eagle parts 9.5 alm. dart pro 1s 310 cc elderbrock air gap 750 demon. What is the best HP and TRQ being built using these parts ? What is max safe RPM? What cam are they using? What exhaust? What fuel pump?

I just went through all this if you are curious search Tech Q&A forum for "Roller Cam upgrade". I used RMbuilder for my cam and valvetrain and highly recomend him. The best service I have found. Not the cheapest but worth the money.

cams
 

is anyone familiar with the Teague Marine cams? Just curious as to the specs of their stage 2 and 3 cams. any input or specs would be great.
Thanks,
John

Just go straght to bob. He will speck the thing for the boat, not just something off the shelf. It really doesn't cost much more in the long run.

I second Bob as well. He is doing my cams and valvetrain as we speak.

Anybody?

what does the cam card say? No way you are buying a cam without a card? Are you?

I wouldn't think they would sell one without a card either?

never mind. some times i am just curious as to cam specs and what all is out there and available. i have expermented with many including custom grinds however i haven't used any of Teagues and was just curious. they can perhaps answer the question. some how i must not have explained what i was looking correctly. my bad...

I think I knew what you were looking for, it would seem that if you called and asked them they would give you the specs.

Here is an oval port head that is the ****z.
http://www.sonnysracingengines.com/c...max-flow-heads

OK---it's abit pricey. Oval or square, it's about your combination of other components. Give RMbuilder an email or PM. Bob knows marine motors. He can also design a cam for YOUR combination. No cookie cutter crap.

RMBuilder/Bob Madara of Marine Kinetics in N.Y. is the man with the cam.......the cam guru and will get you the right cam for YOUR application and what you want to do with it. 585-654-8583

can I get away with 10:1 compression if I use a big roller cam from Bob Madara, iron heads, I'll only use 93 octane? I will eventually get alum heads, but in the meantime they are not in the budget.

The only way I would run that compression is with aluminum heads. On the street it would be fine however as you know in a boat the engine is under a constant load. Kind of like driving a be heavy truck up a steep hill for hours at a time. I would go no more than 9.5 to one. Perhaps use a thicker head gasket with your iron heads and then a thinner one with the alum. Just a thought.
John

If you are serious about doing somthing and ready to spend some money, call Bob Mandera before you buy ANY parts. I just gained 5MPH from a roller cam and matching components. Of course if you are not looking to go fast just buy the generic parts off the shelf.

454 to 496
 

Try calling morgan & son racing engines @ 972-264-6977
they deal in all engines from stock to 800ci and above mostly drag racing but he is the best engine builder in texas