zx6rr33

Has anyone used a Crane 168731 with Gil Magnum Choice exhaust? Did you have any problems with water reversion?

pslonaker

iTrader: (1)

I have installed this cam in more motors than I can remember and never had a reversion issue. It is a great cam for a decent bump, but to get a good benifit from it, you need to be able to turn the motor up to at least 6000 rpm. Twisting the motor to 5000 is only going to net you something like 75% of the cam. Also, if you decide to go to the 741 cam, it will bejust like the 731 and be trouble free regardless of what exhaust you run. You're good.

MILD THUNDER

iTrader: (3)

The 731 cam in a 454 wont need 6000RPM to perform. The 741 cam, maybe close.

The 731 is 226/236 on a 112LSA. The 731 is a nice fit for a mildly built 454.

Keep in mind these cams are gen VI stepped nose cams. I thought I remember you said you had a dart block, I believe your block would take a mark iv/gen v style cam.

zx6rr33

Mine is a Dart block. I'm trying to keep the cost down as well so I'm trying to decide if I should do a roller setup or stay flat tappet. Engine specs are as follows. Dart big M .020 over, weiland dual plane intake, 9.2:1 compression ratio and dart iron eagle 308 heads.

pslonaker

iTrader: (1)

Your compression is down alittle to be running the 731 cam but maybe not enough to be an issue. Expense wise, if you cant seet the spring height for the roller cam, then you are probably going to be looking at something in the $1500.00 range to go with a roller setup. You will need the cam, lifters and springs. If this blows a hole in your budget, then I suggest that you look at a Comp Cams flat tappet setup. This one, http://www.summitracing.com/parts/cca-k11-232-3 will fit your budget and it is also in your compression range. If you want to bump it up alittle, then this one would work great for you... http://www.summitracing.com/parts/cca-k11-240-4 . The 240-4 cam is just above your compression but not enough to matter. In a 454, either cam will give it some attitude around the docks and at an idle, but not enough attitude to become a pain in the butt. Good luck.

MILD THUNDER

iTrader: (3)

cmon, that first cam you recommend is comparable to a stock 454 MAG 365HP cam!!! 218/224* of duration....The stock mercruiser 420HP 454 used a 228/236 530/551 lift 114 lsa flat tappet, with 8.8:1 compression. You are suggesting a much milder flat tappet for his 454, when he's seeking 500hp.

The 731 cam will work just FINE with 9.2:1 compression in his 454. Mercury used a similar cam in their 500EFI, with under 9:1 compression, and a even more aggressive profile in the 525EFI, again, with under 9:1 compression.

218/224*.......its not going in his RV, its going in his boat. No point in sticking a cam that will run out of breath at 4800- 5000 in it.

jamontes

iTrader: (2)

Word!

pslonaker

iTrader: (1)

He doesnt have a 420 HP 454 and the cam I suggested is ALOT bigger then the stocker cam in it from Mercruiser. Besides that you might want to look at the price of the cam you are talking about...if you can find one. You are not going to get 500 HP from a cam swap alone in a 454. He said he had a budget and his motor doesnt have a roller in it now so to go to the 731 it is going to be expensive. he has to get "retro-fit" roller lifters since he cant get a spider plate and the retro roller lifters are going to cost him around $600.00. How many motors have you put together? You really need to look at and understand the cam spec sheet rather than go off what you read on Summit...There is a lot of differences. I build them almost daily and I gave him the information that has worked for many of my customers that were also on a budget. He can do whatever he wants but if he does it wrong he gets to do it all over again.

Griff

The 731 works perfectly fine in a 454. I used it in my 525SC. Idles at about 800rpms.
The 9.2 Comp ratio is fine. Spin it to about 5400rpms and you're good to go.
The 731 is just very slightly larger than a 500efi cam.

HaxbySpeed

Ya Mild Thunder, I bet you don't even have a "magic room"!
Lmao! Where do you do all your machine work shooter??

[YOUTUBE]http://www.youtube.com/watch?v=BMOKvhPis_U&list=PLm2Lymo6NjpCLpJZuoMcGDSF 7nyhyr0hK&index=8[/YOUTUBE]