Is this a good combo to run? 454
 

i have another topic on here that relates to my cam selection but i want to know some of your opinions on the combo i am looking at. the engine is as follows

99 454 "vortec" low hour block and heads from a mpi non mag motor
carter/edelbrock 750 carb
edelbrock performer intake
gil/merc stainless exhaust
crane 731 cam
maybe add roller rockers?
adding new screw in studs to make valvetrain adjustable
springs if i need them
thunderbolt igntion but upgrading to a msd or similar later

i know my engine is not forged but after dumping as much into the boat this year i have to work with what i got here and i am not going for a 80mph boat or anything, i want something decent though. anyone have thoughts on a top speed maybe with this combo in a 89 baja 250 es running a 23 pitch prop? is there anything that i have chose that might not fit the combo? i am thinking a different carb might be coming later also.

That looks similar to what a lot of guys here run. Exept for the internals on that engine are cast not forged. You could bore & stroke it to a 489 or 496 with forged crank, rods and pistons. Those heads should be large ovals with small chambers (good for flat top pistons). However the heads do have small valves. I did a port job and installed larger 2.19/1.88 valves in my large oval heads. Call RMbuilder for your cam, lifter, spring setup. Good Luck!!

65 to 68 mph

i would be happy to be in he mid to upper 60s! so does everyone agree that this will be a decent setp to run for awhile. i think i will swap out the internals to forged next spring and maybe do some head work. i am not sure how many people have been paying attention to what i have been doing but between transom, stringers, floors, all ne interior, wiing and a new motor funds are running low lol. i have everything besides the stuff for the heads right now. thanks for the replies

Dont get your hopes up to high. When I started I had a stock 330HP with 21P prop at 55MPH. Every time I chaged somthing I only gained a couple MPH. If you leave it a 454 and just do the cam, exhaust, manifold and carb. That cam you are looking at will need forged internals to reach peak RPM. You might be looking at 61/62 GPS. Of course on the "Drunk Guy" speedo that would be 70. Take your speedo that reads 3 mph too fast then add a few more for fun:evilb:.

Your intake manifold will be a problem. You need to flow alot to get the vortec heads working. I'm not a big fan of the Carter Edelbrock carb either for flow (cfm). Too much turbulence. I run the same motor, 0.060" over with fly cut dome tops, cut heads to match, slight port and flow work with a Victor Jnr manifold. I was going to run a Performer RPM Air Gap, but I found the Victor first! I also run a BG Demon.

With your exhaust (Gil / Risers) you really need to work on steady flow. A better intake manifold (high rise dual plane) would help and you can't beat the RPM Air Gap apparently. You'll also need a good electric pump, I wouldn't run one of those combo fuel / raw water jobbies if you paid me. Try an Aeromotive SS Marine or the Holley Blue pump and a Holley or BG Regulator (for either pump) and you'll be fine.

The 731 cam is good for your combo, RMBuilder could do better of course, but if you're looking for a simple no bull solution now, stick with the 731. Change the intake and upgrade the carb, make sure you use the 4 hole 1 inch (min) spacer on top too!

Oh and for what it's worth, I would also avoid the MSD 6M if you could. The TB IV is good enough if you upgrade the coil to a Blaster 3 or similar with good (MSD 8.5mm) wires. Your motor will be bullet proof!

Good luck mate, let us know how you go! :drink:

thats good that you mantion the intake now, thats one of the things i have not ordered yet. i didnt metion it but i am also gettting the holley blue fue pump and regulator. i agree that the carter wont vut it for long but i got a super deal on it rebuilt and it will do me alright until the wallet recovers from all of the other stuff. this makes me feel pretty confident about the combo, it works with what i have and i think it will leave from for improvements over time.

1. :confused: You are going to upgrade and thinking of not doing roller rockers.

2. I really do not see a problem with not having a forged bottom in this application, you are going to be well under 500 HP and their were quite allot of builds done on 454's that have cast bottoms that are under 500 HP if you do a search. (I am no expert just an opinion)

3. Speed prediction......a true 63mph GPS

- I like you cam selection
- Intake I like the Weiand Stealth
- Electric fuel pump as stated earlier
- Do not know much about your heads

JMO

I have a great deal on the perfect cam for what you have. here ar the spec's
MERCRUISER 454 502 MAGNUM ROLLER
MERCRUISER # 431-850478 / GM#12551622
.004 300*/ 300*
.006 288*/288*
.050” 224*/224*
.200” 125*/125*
Lift .483”/. 483”
ICL 109*
LSA 115.5*

http://cgi.ebay.com/ebaymotors/454-5...1%7C240%3A1318

Good cam, not as much lift as the 731 with a bit more LSA and less duration.

With the smaller valves on the Vortec's you need lift ( ~ .530 - .600") so I'd stick with the 731 if you want the best power for your combo.

Not trying to cut you off Rock, just my 2 cents (for what little it's worth with the exchange rate and all...)

I would stick with the 731 or call Bob for a grind to fit your needs. Sounds like you just want a relatively simple inexpensive upgrade. You will want something over or around the .565 lift with around 225-230 duration. The other cam mentioned for sale I'm sure is a fine cam but is closer to a stock application and you won't see much gains.

i sent payment today on the 731 cam so thats what i am sticking with. i want to build a more built motor maybe as soon as next spring but i need to be on the water this year so i guess i am trying to buy parts that will work with my simple combo this year and also be good for a higher hp application next year. i am not thinking anything crazy, i just dont want to be passed by similar boats with stock motors around my area which is not too many.

You'll be happy with the 731 trust me, it'll do the trick!

Your combo should fit quite nicely together now. Well done!

Did you get that RPM Air Gap Manifold yet?

Let me know how you get on when It's up and running!

im working on getting a air gap and blue holley pump/regulator, i am doing it as fast as the wallet will let me lol. i might have a holley carb coming soon also. i will post some pics as soon as the motor starts going together.

cam is here, i am looking into springs and the studs, retainers...... or do i really even need them? i have done cam swaps in my small blocks and never messed with springs or anything and i have yet to have a problem with any of them... as far as roller rockers go, will the cheap 130 or so dollar ones on ebay hold up? i have used those also on small chevys with great luck but i know boats are more abusive... i am still looking for a deal on a air gap but that is for sure what i am going with. the cam is here, it is the copper/bronze one so thats good from what i have read. as soon as the weather improves i can get the transom and stringers installed and then the motor is next on the priority list, i have everything except the head parts, intake and fuel pump, after that it should all be coming to together very well. :ernaehrung004:

Get the springs that match the cam. Comp 929's at the least, Isky 8205 or 8205 plus are better. I use Isky 8205 plus. Be sure you have the correct spring height set. Use Crane or Comp adjustable roller rockers? I use the Comp. Be sure you set it up correctly or it will BLOW.

i am trying to do roller rockers but i can seem to find the correct studs to bolt into my heads. i am thinking stud girdle also.... do i need new push rods or will the stock ones work ok?

I think Gen V & VI heads use a smaller thread for the studs. I have a set that go with some peanut port heads I am trying to sell. Mark IV studs are larger and will not fit. Will that cam work with stock lifters? I use PBM (Morals) lifters. I just when through this and if you do not do it perfectly you may have problems. Get 3/8 crome molley one piece push rods. Do the sharpie test and make sure you have the correct lenght.

i have scorpion roller rockers in the mail right now, i did some research on them and i heard good reviews, made in u.s. and lifetime warantee, scored a good used set for 100 shipped! i am working on intakes, is the air gap my only option? i am building this boat on a tight budget and every dollar i can save can go a long ways! so if i can get a used intake then that will help, thing is bbc parts are common but not common enough to sell cheap so if there are other intakes i can be searching for then that will help. there is a new one closing on ebay in 30 minutes that i might snag but it isnt cheap still. any other ideas or anyone have a used one for sale? jeff are those studs for the genvi heads? i will buy them if they are, i am looking at 75 for new ones, plus springs, retainers and locks. will my stock pushrods work alright? at least for a season? i plan to throw a forged lower end next season so i am looking at a full over haul in the future.......

They are on Gen V heads, I think they will fit Gen VI but I am not sure. They are ARP's.

if those heads had the non adjustable valvetrain and and did not need to be tapped for studs then i think they are the correct ones? what do you want for them? part number? it would help allot! i got isky 8205 springs last night on the cheap so that helped out my list of parts. i still really need a air gap style intake, thats the biggest thing i need right now.

Here are the ones I have. They description says Gen V. They are not that expensive. I was going to include them with the heads I have for sale. http://www.jegs.com/i/ARP/070/135-7102/10002/-1

I'm not sure if they're any good, but Ebay motors has those Cross-Wind Airgap knock off's. They are what looks to be a simple copy of the proper edelbrock performer rpm air-gap without the labels. I don't know if there's any big differences but i've compared pics of my old air gap which I sold with the pics on ebay and I can't spot any differences. You might save some money there!

You only need to change you pushrods if you've changed your lifters. The rockers can change if you find the correct studs. If you got the longer shaft lifters than you NEED the slightly shorter rods. As far as I've ever been able to find, you can run a fully stock valve-train combo with the 731 cam, but if you're going to push hard, you really should upgrade the springs first if anything else.

those cross wind intakes are almost the same price as a edelbrock which i dont get? so i would rather just pay for a name brand on that one. will the stock retainers and locks work with my combo and the isky 8205 springs? or do those need to be replaced also? i was planning to replace them but i will have almost as much in retainers and locks as i will my roller rockers. the second layer of my transom went in last night and the stringers should be easy so i am hoping to be done with the wood work by the end of the weekend and then i am going full force on the motor.

I read on in a Chev book that the Gen VI locks & retainers are actually quite good and so long as you're running the correct height springs you shouldn't have a problem. I'll read up on the 8205 Isky's but I don't think they have a different seat height.

Good luck on the Transom and Stringers.

The crosswinds are just china made knock offs. They are made by a company called professional products. I have owned one in the past and the only difference, that i could tell was the casting wasnt as pretty. Ive even seen dyno comparisons that equal edelbrock and sometimes exceed their performance.

i have one on a small block and i have never gotten the thing to seal correctly. i think they are almost the same price on ebay as a edelbrock so i would rather go with the safe bet on that one. are there any other companies that make them?

I'm with you there, I thought you could get them for quite a bit cheaper but if they're asking nearly the same, the name brand is worth it! I've had a few Edelbrock manifolds and I've always found them to be the best quality.

Apparently the Weiand Stealth isn't too bad, but I've never tried. Not as high as the RPM Air Gap though.

It wouldn't kill you to run a single plane, just don't get a crazy race one. Let's face it, most of us are either at idle or WOT most of the time anyway, and a boat that doesn't behave well at low speed isn't bad, it just 'has character!' :evilb:

Air Gap on Ebay (rect port) for ~$150
http://cgi.ebay.com/ebaymotors/Edelb...1%7C240%3A1318

Ends in 1hr 35 though so hurry!

Oval Port non Air Gap - $50:
http://cgi.ebay.com/ebaymotors/BBC-E...1%7C240%3A1318

Ends is 22Hrs.

o have large oval ports so that one wouldnt have worked, i saw it though. i have been searching ebay but it seems like the used ones sell within 50 bucks of a new one, in that case i would just rather go new since i have had issues with cracks and bad threads with past used intakes on other motors. any one have a used holley blue fuel pump and reg they wanna let go cheap? these are my last 2 major items for the motor. the wood/glass is getting close to done!

i just ran across this thread again, i bought a edelbrock air gap and its sitting at the house waiting on my heads to get done. now i am having a huge debate on fuel pumps, i can get a holley blue for 95 shipped new or do i go to mallory and buy a used 140 or 110?

MALLORY!

Avoid the Holley like the plague or you'll wind up buying a Mallory later to replace your dead Holley Blue!