460 ford cam

[millerman]

i have a 460, just rebuilt at the local engine shop, and a rebuilt berkeley jet with an A impeller. just installed a performance dist. marine DUI unit and a holley 750. only getting 52mph @ 4000 rpm (pedal to the floor) and i think i need to recam. what is the max duration and lift in a cam i can get with stock heads?
thanks

[twowheeledfish]

Something is definitely wrong. I have a bone-stock 460 that spins 4800 @ 71 mph. Wet logs, thru transom 3.5" exhaust, berk A impeller, american turbine bowl. A cam won't do much without some head work. Wait for LakesOnly to reply... he'll need more info on your setup.

[malcolm]

Get out your list of parts and post them up. Everyone's going to want to know what you've got in there. Head casting #s too.

[SmokinLowriderSS]

i have a 460, just rebuilt at the local engine shop, and a rebuilt berkeley jet with an A impeller. just installed a performance dist. marine DUI unit and a holley 750. only getting 52mph @ 4000 rpm (pedal to the floor) and i think i need to recam. what is the max duration and lift in a cam i can get with stock heads?
thanks
Yep, parts list that cam data, I'm smelling a bad missmatch for the intended purpose. I'm thinking the cam duration is going to be close to 300* seat to seat, I think that's about 250* @.050", which is going to KILL lower RPM torque/HP production.
You didn't have the heads ported a bunch for "freer high-RPM breathing" did you? Those ford heads have IMO pretty darned huge ports already, bigger can cause a lot of flow velocity trouble in the 4-5,500 RPM range.
Berk "A" absorbs aprox 202HP @4,000 RPM, that's all it's making there.
My bone stock 454 ran a .461/.480" x 262*/274* cam, only made 280/290HP, at 4K, but spun the stockly fed Berk 4850RPM all day long. Over 400 pounds torque untill arround 3700 RPM.
.565" lift, 232* duration cam, headers, intake, I spin that impeller 5,000 RPM with a good loader in front of it. 400HP, about 350@4K. over 400 pounds torque all the way to 5-grand, over 450 to aprox 4300.
Boat engines, including jet boat engines are MUCH different animals than car hot-rod engines. What you really need except for full racing machines is a high-RPM truck engine. That means good to great torque production down low in the RPM range and the ability to carry/sustain that torque production into the higher revs.
All the HP in the world at 6,500 RPM won't do you squat if you cannot GET to that RPM.

[1968Droptop]

Paul (Lakes Only) will chime in soon I'm sure, and he's got a litle experience with BBF's :D Curious, you said you just installed a distributor. Is it timed correctly ?

[FILUCKY]

Sounds like a typical stock long block built for a car in a boat, jet boats like more cam, intake and carburation than a car. I would be looking for a cam in the .550 lift and 240-250*@.50 duration installed @ 4* advanced with a victor style intake and a holley 850dp and timming about 32* for a good start.

[malcolm]

A big cam isn't going to help much if you're running D3 heads. :(
I'm thinking there's just something "stupid" going on there. Is it running smooth right up to that rpm or is it surging? Big blocks need an incredible amount of fuel past 4000 rpm.

[LakesOnly]

i have a 460, just rebuilt at the local engine shop, and a rebuilt berkeley jet with an A impeller. just installed a performance dist. marine DUI unit and a holley 750. only getting 52mph @ 4000 rpm (pedal to the floor) and i think i need to recam. what is the max duration and lift in a cam i can get with stock heads?
thanksMillerman,
OEM 460's (car or marine) will turn several hundred more rpm than your new high performance engine is managing. There is a grave error in your engine...could possibly the overall combination, or the way it was assembled, or your current state of tune. Please post ALL engine specs, including cylinder head casting numbers or brand/type, bore and stroke, etc, all the way down to parts used.
just installed a performance dist. marine DUI unit and a holley 750. only getting 52mph @ 4000 rpm (pedal to the floor)...Millerman,
Did you run the engine before you installed these components? And if so, how did it perform then?
LO

[millerman]

I'll have to call the shop on monday for bore and stroke. Heads are stamped D3VE-A2A, i'm assuming stock ford??. Stock Ford dual plane intake manifold w/ 1 inch carb spacer. Distributor is a Performance Distrib. DUI Marine 7000 that is correctly timed, plugs gapped to .055". Pump is a Berkeley 12JG- A with diverter. Running wet thru transom logs. Holley Marine 750 double pumper with mech. secondaries. I had a holley 600 on it and thought the low rpm's were because of it, got same results with the 750. When I had it rebuilt it was a used block, installed forged pistons but kept the rest stock except for marine seals. Wanted reliability over everything but expected more than 4000 rpm. I went to a real marine engine shop and had it professionally timed and carb tuned. I never ran this engine without the parts on it now, except for the carb. From 0-52 the boat is a rocket, but she just won't turn any more rpm's than that. All research i've done points to the camshaft. I'm guessing it currently has an RV cam because the idle is super smooth and lower rpm running is phenominal. I don't know what cam these heads will accept without head work. I will repost the engine specs tomorrow after i call the shop that rebuilt it.
thanks

[4604me]

[QUOTE=millerman;2436606]i have a 460, just rebuilt at the local engine shop, and a rebuilt berkeley jet with an A impeller. are you sure that's a A. impeller and not a AA

[spectras only]

Harman marine used to put a mild cam around 496/500 lift into their marine 460 with the A2A heads , topping it with the mismatched SCJ cast intake and a 750 vac secondary carb on top.It was rated at a conservative 320 HP , spinning a berkeley "A" impeller in a JC bowl . 5000 rpm was average. Something is definitely wrong with your setup , only turning 4000 .:idea:
I like the Ford motorsport A443 cam in the 460 .

[SmokinLowriderSS]

OK, what style pistons are in it, how big of a dish/dome/flat-top?
How far below the deck top do the pistons stop at TDC (trying to get comp ratio here).
With assumptions of flat-tops and "0" deck height, (.040" gasket) I get a CR of 10.3:1. I'm trying to set up an electronic dyno build here to aid in problem diagnosis.
I found stock flow data for your heads.
I need all your cam data.
Entirely valid concern over impeller cut size. a "AA" takes a LOT more muscle to crank it hard than an "A" does.
I'm still smelling a BAD parts miss-match someplace. Give us enough info and we'll help you figure it out. :idea:

[millerman]

just got back from havasu and got the specs.
460 bored .030 over
cam duration 218/218 @.050
lift .528
2000-4500-rpm
9.8:1 CR
performance distributors marine 7000 mech advance dist.
holley 750 marine double pumper with mech secondaries
thru transom wet logs
91 octane

[cstraub]

Stock BBF heads with a single pattern cam. . . nope. That Ford needs some duration split to crutch that exhaust port. The engine is smoothering.

[460 jus getn it]

Something else is going on. Those specs with a "A" should get you over 4k rpm. I have a mild 466 ford, and i spin a "A" TO 5200.
HYDRAULIC-Jet boat with A or B Hyd. Hyd. 2000 to 6000 34-331-4 280H 280 280 230 230 .530 .530 110°
This is the cam i have, its a small can for the motor.

[LakesOnly]

460 bored .030 over
cam duration 218/218 @.050
lift .528
2000-4500-rpm
9.8:1 CR
performance distributors marine 7000 mech advance dist.
holley 750 marine double pumper with mech secondaries
thru transom wet logs
91 octaneBased on the information provided, your engine should be turning another 500 rpm minimum and possibly more.
Based on the information not provided, there can still be many reasons why it is not.
The cam is slightly more aggressive than the stock marine cam...or is it? (What is the LSA?) Also, since we can only take shots in the dark at this point, I am beginning to wonder if your cam timing is off (defective timing gear broached incorrectly) or your lifters are too preloaded, etc.
I think this engine should be running quite a bit better than it is (it certainly has the potential); also, I agree with Straub about the advantage of the split duration profile with the unported D3's.
LO

[IMPATIENT 1]

buy a crane bbf rocker arm conversion kit, some good double springs/retainers/locks and some roller rockers. most machine shops just shim up a weak valve spring and weak springs kill rpm potential! i just went thru some heads that were "reman'd" and the seat pressure was 50:jawdrop: i had the spring pockets cut for double springs, set the new springs at 100 and it should be good to go, easy on the hyd. big lift cam too;)
guys, if your running big lift or big duration cams, you need to buy a spring tester, at least the moroso spring pressure tester dealio to watch for spring failure, i see so many guys run hyd cams that are leaving alot of rpm's on the table with weak stock springs.if the springs don't match the cam requires, what's the point of buy a performance cam??????

[SmokinLowriderSS]

if the springs don't match the cam requires, what's the point of buy a performance cam??????
The very reason I advise people to buy the springs from the cam maker that reccomends them for the cam.

[IMPATIENT 1]

The very reason I advise people to buy the springs from the cam maker that reccomends them for the cam.
yepper, sure takes the guess work out of it! most weekend warrior boaters don't think about relaxing springs for the winter or even know what seat pressure/open pressure mean, those are the same guys i spend a nice day on the lake towing in:D
combo nation my friend , its all about the combo:devil: