92rs85berlintta

iTrader: (1)

im not a cam expert by any means but i just got off the phone with comp cams and they said to use this cam i told him a want a streetable cam that would be good for a 355 matched ported 601 heads and a lt1 intake conversion.

says its a boat cam?? do the specs look like somthing im gonna want to use on this engine?

thanks

ME Leigh

That actually looks like a pretty good cam. I hugely favors the exhaust which is a good thing with the 305 heads.

92rs85berlintta

iTrader: (1)

what about with injection? what should i expect as far as performance? im still learning the whole reading cam specs deal. i believe the lsa is 112 witch is ok for lt1 injection i think. i just want to make sure i can utilize the best performane of my engine with the lt1 intake.

Stekman

It uses marine lobes, not that there is anything wrong with that. But the ramp rates are a bit quicker. For example i will compare to the XR269HR which is an EFI Xtreme Energy grind. It has 218/224 @ .050" with 269/276 seat duration. The one you post has roughly the same seat, but 226/236 @ .050" so the valve is opened faster. You will def. want to run the recommended spring to control the lifter. As for how it will perform, it shouldn't be too bad. The valve timing looks similar between the 2. Specifically the intake closing event, the marine cam is pretty much 3 degrees "slower" so to speak than the 269hr EFI cam. And for EFI, that's the big part of the valve timing. It is also even more heavily favored towards the exhaust side than the EFi cam. I think with a bit of tuning it would work pretty well. Again, run the recommended valve springs.

ME Leigh

Stekman is right, that cam does have very fast ramp rates. I wonder why they don't use that lobe design for there XE street cams. I wonder if it is too radical and there are reliablity and durability issues. Since boats usually run at a constant high rpm, unlike the street.

92rs85berlintta

iTrader: (1)

I hope theres no issues like that i would hate to put this thing all together and have it not perform as well as i want or not be reliable.

if they are that close i wonder why i wasnt recomended that one. maybee because of the 305 heads i guess????

so does that mean that this cam is better or worse than using the xr grind. not sure if that means its a good thing or bad.

thanks again guys

ME Leigh

The XR grinds are roller cams, the XE cams are hydraulic flat-tappet. The XRXXXHR is a hydrauilc roller cam, the XRXXXR is a solid roller cam.

350camaro

Is a marine smallblock chevy a standard or reverse rotation engine?

Stekman

Oops. I shouldn't post so early in the morning. I used the EFI roller, not EFI flat like i should have. Doh.

92rs85berlintta

iTrader: (1)

so actualy they were more or less just keeping me as close to the same specs as the roller xr mentioned just in the hydro flat tapet style cam.

92rs85berlintta

iTrader: (1)

just out of curiosity how much estimated hp should i expect from somthing like this combo?


im pretty sure there standard 350 engines

92rs85berlintta

iTrader: (1)

what about spark plugs. is this cam going to give me black plugs all the time. my edel blackens plugs no matter what. i want to stay away from that.

Mkos1980

iTrader: (8)

We have duel Chevy 350's in our 93 SeaRay 30FT and one is standand and one is reverse rotation. Helps for better control of the boat.

BadSS

There’s really no difference in the rise rate when comparing the XE268 intake lobe to the XM270 intake lobe (both flat tappet cams)

226/270 = 83.71% - 480 lift/270 = 1.7778 - 480/226 = 2.1239
224/268 = 83.59% - 477 lift/268 = 1.7799 - 477/224 = 2.1295

It's true that the larger the seat duration, the quicker you can bring in duration at .050 without digging the side of the lifter into the cam. With a variance of 2 degrees, even taking it to the “Xtreme”, the rate of rise difference is going to be minimal (both with maximum rise rates). Looking at the percentages above, one could assume the marine lobe is fractionally quicker based on the slight percentage difference. However,,, apply the percentages in reverse logic to the other cam. 268 x .8371 = 224.34 and 270 x .8359 = 225.69,, they’re still “224” and “226” cams. One really can’t say one cam is faster than the other (from .006 to .050 lift) until you swap the percentages around and get different numbers. As far as we know that “224” cam (268) could be 224.18 degrees and the “226” (270) could be 225.86 degrees and if so the .050/.006 percentages would be equal - IF,,, and I repeat IF the .006 duration is EXACTLY 268 and 270 degrees.

As for as cam advice / recommendations and a HP guess; The 2.02/1.60 valves with a 58cc chambers could mean they could flow better,,, or possibly worse than a properly pocket ported set with 1.84/1.50 valves. It depends on what all was done to the heads and if it was done correctly - no offense meant. For me (or anyone else) to be able to give a decent cam recommendation, “we” need to know everything about the heads --- if you don't already know the flow numbers and runner volumes.

Things like: Did you contract someone to do the work and if so how much did he charge. Did you get theses from someone that already had them worked and if so,,, how much did he pay for them? What did he run them on (350 / 400 and as much detail as possible), and how fast was the car? How well did he do at the track if it was a circle track car.
Like I said,,, anything and everything helps to make a reasonable guess at what they could flow.

92rs85berlintta

iTrader: (1)

thanks for the cam info it realy helps me decide. if im picking it up right these cams are not that far off at all. then why was i recomened one with slightly quiker ramp rates? also how is this cam going to be on the street. i just dont like the cam i have now because it blackens plugs and doesnt like to go less than 1/2 throttle.also its terrible with my heads.i can get the air in with ease but i can get it out. since i will be using this on the street i need a little better drivability than the edel is giving me of course with decent hp.every street machines goal i guess. i dont mind a lopey idle as long as it idles.

ok as for the heads.601s. i dont know too much about them other than the fact that they were milled, cut for bigger valves, hardened pushrod sleeves,3 angle job, high lift springs, screw in studs w/guideplates. i wish i could remember the rest. i know the valves are 2,02 1.60 but they are not ported yet. im still trying to decide wether i would be better off with lt1 head conversion or just porting these. im trying to save money everywere possible and since i have a kid on the way every cent helps.

on another note i got my 1tl intake today and begain the tranformation.

Auggie

Well, how about that they have a lot of them "Marine " cams and its time to find a home for them. Just a thought.

Auggie

BadSS

There isn't really any difference in the rise rate of the XM marine and "regular" XE cams.

The reason they recommended the marine cam was the 112 spread and 10 degree spread on the exhaust for the E/I ratio they were estimating. The 112 spread helps to reduce the overlap compared to a 110 spread.

example - these cams will have similar idle characteristics
226/236 - 112 with 4 degrees advancement
224/230 - 110 installed straight up

They have the same overlap and installed as stated will give similar cranking compression.

If the heads don't have a good exhaust to intake flow ratio (E/I), the 223/236 - 112 cam at 4 degrees would perform better - compared to the 224/230 - 110 cam

Based on what you've said,, if the heads were not ported and the chambers were not worked to properly unshoud the larger valve,,, it very possible the overall flow may not be much if any better than stock. So,,, I'd say the 226/236 on a 112 would be a good choice for you.

However,,,,, with the heads you have now,,,, if you want to be positive to get a clean idle and good midrange throttle,,, you might want to go with the X4262H it's the Xtreme 4x4 cam - 218/226 - 111 It has 8 degrees more on the exhaust to help with weak E/I ratios and a little tighter lobe spread (compared to the marine cam) so the power will come in a little sooner and be a little more peaky with a little less rpm range. You heads are not going to support a lot of RPM even though the LT1 intake is going to want to take the engine up high. I’d install this cam either at 111 degrees intake centerline if you want a little more top end or with 2 degrees advancement if you would rather have a little extra throttle response.

Honestly, it is hard to say,,, knowing that you can buy a brand new set of Vortec heads for less money than it would cost to pay someone to do the 305 heads and get comparable flow numbers,,, its hard to recommend having to pay someone to work the 305 heads. If you could do it yourself,,, things would be different because the 305 heads can do very well when worked right. You already have the larger valves installed,,, so it’s possible it could be more cost effective at this point – can’t comment on the LT1 head conversion – don’t know enough about it. Seems like by the time you prepped and converted the LT1 heads you would be close to the cost of a set of new Vortec heads,,, but as I said,, I've never looked into converting them.

92rs85berlintta

iTrader: (1)

i looked at the vortec heads because of there flow potential. however thay wont work with my lt1 intake and efi setup.


im trying to stay away from lowerend tq numbers and get closer to higher end horsepower. i thought about going for low end but if i was to do that i would just get a tpi setup with the cam you mentioned.



my plan was to port them. if they are ported some flow as good or better than a set of vortecs. assuming they are ported,would i be able to use these along with the xm270 to get rather good hp results??

thanks again

BadSS

Absolutely, but it'll depend on the E/I flow ratio after they're ported and exhaust system you're using whether you would be better off going with the XM, 4XE, or regular XE cam. You either need the extra duration or you don't,,, you either want a wider lobe spread or you don't. There's nothing special about the lobes on the XM cams compared to the others,,, other than the difference in added exhaust duration (split) and the lobe seperation (spread).

BadSS

I was trying to be supportive of your LT1 EFI conversion and don’t want to discourage you from giving it a try, but it’s been bothering me knowing your money is tight with the new kid on the way,,, and knowing that the money you're going to put in the EFI intake MAY not be worth the performance gain you’re going to see – unless you got EVERYTHING (intake, t/b, injectors, wiring harness, computer, sensors, fuel pump, fuel lines, etc) really REALLY cheap. Plus,,, unless you get the equipment to burn your own chips (around $200), or go with an aftermarket computer system on the EFI (around $800), already have a laptop, or scanning tool - which is critical,,, there’s no guarantee and,,, in my opinion (especially if you go with the speed density system),,, less of a chance the EFI will be any more efficient than a properly tuned carbed.

One thing I know is hard to tune is a big cam on a tight lobe spread (like you have) with a restrictive exhaust system.

Let me ask you what size Y-pipe and the size pipe you have running to the Flowmaster,,, and is it a dual exit muffler?

If you don’t have a 2.25” Y-pipe to a 3” intermediate pipe,,, you need that as a minimum. If you have a dual outlet Flowmaster,,, kick it to the curb – terrible muffler not much better than stock and with the size cam you’re running old design 232/234 on a 108 lobe spread – free flowing exhaust it CRITICAL. Best muffler in my opinion if you want dual outlets is the race series Dynomax, it’s around $100. If a single outlet will work for you, their single inlet/outlet 3” race series is around $65. If the Flowmaster you have is a single 3” inlet/outlet 40 or 50 series,,, it’s marginally OK for the engine combo you currently have.

Here’s my suggestion,,, based on almost 25 years of building engines and tuning / trouble shooting performance cars,,, for what it’s worth to you. Buy a book on tuning the Edelbrock / Carter carbs if you’re not 100% comfortable already in tricking one out --- BEFORE you swap intakes. Do the exhaust first (if not up to minimals above) and tune the carb (via tricks you picked up from the book – if you don’t already know them), then change to the XM 226/236 – 112 cam and tune the carb, then convert to the LT1 – if you’re still not happy.

The 7101 intake you have is a good intake and once you learn the tricks on the Edelbrock carb,, especially after changing cams,,, you might be surprised at how well it runs without EFI. I know it may seem like extra work and you might as well change the intakes and convert to EFI while you’re changing the cam,,, but I promise you,,, unless you’re relatively experienced in trouble shooting and tuning EFI systems,,, you’ll be glad you did one change at the time.

92rs85berlintta

iTrader: (1)

i already have everything except the harness and a chip for it and im converting the intake myself. the reason im not staying carb is because i need to pass visual inspection in my state. im adding a external egr setup to it that i have as well. i would rather stay with carb but the boys in the offices decide i cant do that. heres my deal the car was built in florida were theres no inspection so it didnt realy matter what i did and didnt have because no one checked. then i moved to new york and am faced with a decision option A either get rid of the camaro wich i have all this time and money into. i would never be able to sell it for anything because nobody wants a car you cant inspect. or my option b convert to injection that will pass visual inspection. so i guess im goin B. however trying to keep as much power as possible.

2.5 to a dual exit i think its like an 80 series???certainly needs a upgrade wich is planned for next spring.probraly dual 3 inch cats to 3 inch all the way back to an undecided muffler.

thanks again

BadSS

Ah,,, I see says the blind man. EFI makes perfect sense now.

A single 2.5 pipe to the dual outlet Flowmaster is definitely giving you tuning troubles now,,, but won't be quite as bad once you go with a smaller cam with wider lobe spreads. Still,, I'm glad to see you have an upgrade planned.

92rs85berlintta

iTrader: (1)

now im starting to wonder if maybee i should just get a lt1 and put it in. that would give me about the same horsepower give or take some. my bosses friend just bought one for 800$ shipped with 60k on it without a harness and ecm tho. not sure wich is cheaper yet im still weighing the pros and cons. thanks for all your help.

:hail: