454 Mags

[glassdave]

just looking for a guess on what to expect. I have the 454 Mags out of my ScarabIII being redone and i have the following stuff going in. Im not looking for any type of big power but want to wake them up a bit while their out.


Edelbrock RPM-Air Gaps oval port intakes going on square port heads
Crane Powermax H-286-2 cam 226/236, .534/.553 on a 112 lobe sep.
Crane Gold roller rockers 1.70's (Thanks again Mr.Patriyacht )
Pretty much stock everything else.


Anybody have a suggestion on carbs?
Would the stock Q jets work?
Will i see any gains with an after market carb with this package?
Bump the cam timing?

Again not trying to get any big numbers but would like to be in the 450hp range with this boat.


I probably posted this same thread a long time ago

[Blue Thunder]

just looking for a guess on what to expect. I have the 454 Mags out of my ScarabIII being redone and i have the following stuff going in. Im not looking for any type of big power but want to wake them up a bit while their out.


Edelbrock RPM-Air Gaps oval port intakes going on square port heads
Crane Powermax H-286-2 cam 226/236, .534/.553 on a 112 lobe sep.
Crane Gold roller rockers 1.70's (Thanks again Mr.Patriyacht )
Pretty much stock everything else.


Anybody have a suggestion on carbs?
Would the stock Q jets work?
Will i see any gains with an after market carb with this package?
Bump the cam timing?

Again not trying to get any big numbers but would like to be in the 450hp range with this boat.


I probably posted this same thread a long time ago

A 750 dp holley would be about perfect, an 800 dp holley would be good too. The qjet will work but you need to tune it. I'd go with the holley

Load the cam per the cam card, anything else is sub optimal.

The best adder you could do is some true length runner exhaust like the KE, that is if you don't already have good exhaust.

Also, make sure that intake/head combo has the runners lining up proper. I always wanted to try that and think it will work well. Let us know.

BT

[glassdave]

i agree exhaust is going to be worth the effort and probably that would tie all this together. I was thinking the Dana Torque Flows, seem pretty reasonable. I had a boat with KE's on it and its a fantastic manifold. Tell ya the truth though, i didnt care for how they sounded inside the boat. To me it sounded like a chevy truck with the muffler off. Please nobody slam me for this, really their a great manifold. I had somebody take the boat out once while i stayed on shore and they sounded friggn awesome but something about inside the cockpit. Maybe its just me lol besides there more than i want to put in this boat. Anybody got any GIL's they want to get rid of?

I had heard good things about running round port manifolds on square port heads so i figured i'd give it a shot.

guess I'll start lookin for some Hollys to

[Buoy]

Get ahold of ITTLFLI here on the board.
You are looking for about the same build I was looking for.
He's in Cinci, and his Dad does the work.
Great guys.

[Ratickle]

I had heard good things about running round port manifolds on square port heads so i figured i'd give it a shot.

Hummmm, I gotta find out now. Doesn't make sense to me. I'll call my engine builder today. He does the design on intakes and head porting for most the main NASCAR guys.

[PatriYacht]

just looking for a guess on what to expect. I have the 454 Mags out of my ScarabIII being redone and i have the following stuff going in. Im not looking for any type of big power but want to wake them up a bit while their out.


Edelbrock RPM-Air Gaps oval port intakes going on square port heads
Crane Powermax H-286-2 cam 226/236, .534/.553 on a 112 lobe sep.
Crane Gold roller rockers 1.70's (Thanks again Mr.Patriyacht )
Pretty much stock everything else.


Anybody have a suggestion on carbs?
Would the stock Q jets work?
Will i see any gains with an after market carb with this package?
Bump the cam timing?

Again not trying to get any big numbers but would like to be in the 450hp range with this boat.


I probably posted this same thread a long time ago

You're welcome Dave. Thanks for helping us out with the impellor. It was a good trade for us.

The Q-jet will want to be tuned to work with the new cam. They're so hard to find jets and rods for, I'd just find a couple of Holleys for it. See if anyone has some old hp 500 carbs for sale. They are 800's and they are fairly common. The rest sounds good.

[Griff]

I did a similar build up on my 454mag in my Baja. I used an Hp500 800cfm carb on the stock intake with a 1" open spacer and the same cam as you. I milled my heads .020 as well and should have gone .030. Based on my speed gains, I was around 420hp. I picked up about 400-450rpms and about 5 mph.

I gave the specs to guy on OSO a while back and he dynoed at 425hp around 5000rpms using a better intake manifold.

[glassdave]

I did a similar build up on my 454mag in my Baja. I used an Hp500 800cfm carb on the stock intake with a 1" open spacer and the same cam as you. I milled my heads .020 as well and should have gone .030. Based on my speed gains, I was around 420hp. I picked up about 400-450rpms and about 5 mph.

I gave the specs to guy on OSO a while back and he dynoed at 425hp around 5000rpms using a better intake manifold.

what exhaust? I have the one inch spacers as well.


I have a couple carbs off a Merc 502 Mag. Webers i believe, would they be worth trying? they are marine carbs.

[Blue Thunder]

Hummmm, I gotta find out now. Doesn't make sense to me. I'll call my engine builder today. He does the design on intakes and head porting for most the main NASCAR guys.

The rect port heads are too big for a 454 at 5000rpm. Creates lazy flow. The smaller oval port intake will increase flow velocity going into the head and pack more mix at lower rpm. It should help out the engine throughout the intended rpm band. I'm just not sure that intake is one that works doing that. I thought it was a holley intake maybe.

[glassdave]

i thought it worked by virtue of just the oval port on rect port heads. oh well, already got the Air Gaps so hope it still works

[MILD THUNDER]

Theres a carb shop on the west coast that used to have all the q-jet metering rods, jets, etc. I'll try to find them on the net. I actually used to like the Qjet when i had my built Pontiac 400. Although I think the Holley 800 would be my choice in your app.

I also think the stock 365HP rect port heads are too big for a 454. When I redid my 420's, for what I spent redoing my stock heads, I woulda been better of selling them and going with some smaller cc heads, like dart iron eagles or similiar or some afr heads woulda been nice. Going to a hyd roller cam would be a nice upgrade for you.

[StraightJacket]

Built up some 420 hp motors last year. .030 over , 990 casting heads a little touched up , all ARP bolts, 1.7 rollers rockers and girdles, Hyd flat tappet cam don't remember that specs, stock Intake with spacer and an hp 750 carb . made 550 hp , 500 ft lbs , had gill dry exhaust on it and it sounded raspy as all he!! . Pushed a 90TG to 70mph. was actually pretty impressed with the set up.

[Ratickle]

The rect port heads are too big for a 454 at 5000rpm. Creates lazy flow. The smaller oval port intake will increase flow velocity going into the head and pack more mix at lower rpm. It should help out the engine throughout the intended rpm band. I'm just not sure that intake is one that works doing that. I thought it was a holley intake maybe.

I thought on the big ports you left the top of the runners matched to the intake and raised the bottom of the port to increase flow speed and reduce the radius of the change in direction?

[Griff]

what exhaust? I have the one inch spacers as well.


I have a couple carbs off a Merc 502 Mag. Webers i believe, would they be worth trying? they are marine carbs.

I ran Imco exhaust.

The Webers are known to be hard starting as they tend to leaak the fuel out as they get older. I had a Weber as OEM before I did the mods and it was hard to start after sitting for more than a day.

[MILD THUNDER]

What type of cam came in the old HP450 motors? I thought they were 454CI, 990 heads, dart single plane intakes, holley 800, roller rockers, etc. I think it was a pretty similar setup to the HP465, only that it was a 454 block, and made 15 less HP than the 502. Didnt merc also make a 454/460HP back in the 80's?

[bajabob 718]

http://philadelphia.craigslist.org/boa/1112302103.html dave i run stainless marine .here a good price on pair

[Blue Thunder]

I thought on the big ports you left the top of the runners matched to the intake and raised the bottom of the port to increase flow speed and reduce the radius of the change in direction?

Wedges. Same idea.