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Discussion Starter #1
Hey there people, Im a freshy to this forum and wanting to get
some feedback as to the HP Im trying to get from my 351C.
Im aiming for around the 500HP mark and the bits I have to do
this with are as follows-

2 bolt block
4ma crank
eagle H beam 5.7 rods
will have oil restrictors
Wiseco forged .30 over pistons
Comp ratio around 10.5-1
4V closed chamber heads with ferrea stainless valves
Yella Terra rockers
Offenhauser 360 divided plenum intake
Holley 750VS
Motorsport solid cam
Int dura 310
Ex dura 321
Int lift 580
ex lift 606

Anyones input would be appreciated
 

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The defect being, not having enough oil in the sump for high speed operation. Why on earth would you want to restrict the amount of oil going to your engine? Remember, oil cools the engine as well as lubricates. Ever heard of rocker gear wearing out prematurely because of a lack of lubrication?
 

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I don,t know too much about the offy,is it single or dual plane.I personally think a double pump inthe vicinity of 750 800 cfm is going to shit on a vac sec.I had a 750 v/sec on my 4v 351 on top of a torker intake and wanted to see if an 850 dp would make any difference.Suffice to say i settled on a 800 dp and lost the v/sec.Wiseco make nice pistons but a cam of that size (im assuming [email protected] 50) really should have more than 10.5 to 1.Oil restrictors are a matter of conjecture between clevophiles.there are many pro's and con's .Whilst limiting oil to the top end of the engine can have benefits buy keeping the oil in the sump one must remember that valvesprings need a supply of oil to cool them down.Use a good oversize pan that holds plenty of oil and a standard volume oil pump.using a hi volume pump and standard pan should be avoided.If the oiling thing is an issue with you you can run an external feed line directly to your mains to give them priority oiling.
 

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My cam is Ford Motorsport, same lift as you but just a tad less on the duration you quoted. But me reckons the duration figures you quoted not for 1.73 rocker ratio, because I'm sure my cam grind is the biggest solid Ford Motorsport pruduce.

Either way agree with russ don't waste your time on a vac secondary, 750DP bare minium, 800DP better or even 850DP if the Offie manifold is a high rise type ie funnelweb style.

Also agree 10.5:1 not enough to make best use of those heads and cam, sure it will run on premium unleaded but expect a motor with a lazy/soggy bottom end response at 10.5:1.
 

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Um you cant be serious paull? YOu use a restrictor cos it doesnt need or require that amount of oil going to the top of the engine (SPECIALLY AT HIGHER RPM) in most cases not only can it hurt bearings not using an oil restrictor you can also fill your rockercovers full of oil hence where the (not enough oil in the sump) saying came from. It pumps to much to the top end and cant return it fast enough. I used to drill a little whole in the cam bearing and use that as the cam restrictor and use a little screw in grup screw with a whole in it in the rear of the engine.

Works a treat and im sure u wont find a serious engine runnig a solid or roller cam anywhere that doesnt use one.

U can run higher comp than 10.5 in most cases if the engine is set up right. Use of a vac sec carb on any engine other than stock is pointless unless u have stad gears and no convertor. GO the DP anyday

P.S how much iol do u think your engine puts into the top end with a restictor kit...its AMPLE for the engine to keep valve springs cool ect.

It isnt an issue.
 

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Discussion Starter #9
The offy isn't a high rise, is dual plain tho,
will look for 850DP.
What comp ratio should I be looking at 11-1, 11.5-1?
Engine is going in a ute with toploader and nine inch running
3.0 gears, I should be looking for 3.5's or so?
With all this is the 500HP mark achievable?

Cheers for your input, this is my first build
 

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Is it going to be 100% street driven? If so then you will just get by on 11:1 nicely with BP 98 / Shell Optimax plus maybe a bit of octane booster. But 500HP 351's don't come cheap and I would suggest you need atleast 11.5:1 more likely 12.1 to achieve that realistically and then you would need a mix of Avgas or racing fuel - not cheap.

Flick the Offy, go Funnel Web or Weiand single plane. Even really good dual planes start to lay flat at about 5500 and your cam is good for 6500-7000, maybe more. 3.0 gears will make it a prick to get out of the hole, but great if you live in the outback and do highway driving. But seriously, all depends on end purpose. Optimum 1/4 mile times you would need 4.11's or higher, but 3.5's with a manual would be a reasonable compromise.

Thought about stroking it? Bit easier and cost effective to reach 500HP.
 

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ok cast iron heads will be very hard to tune at 10.5 to 1 , with alloy heads maximum you shold go is 10.5 u can get as high as 10.8 on 98 octane but a bad batch and your car is gona start pinging so as a rule you should allow for a margin of error.

If you want to make more power then u may as well go for 11.5 to 1 -12.0 to 1 (avgas) a cam in the 246 range will work quiet well on 98 octane at 10 to 1 but anything bigger needs more compression.

that sort of cam will need big revs b4 it works u wont go anywhere with 3.0s and with a manual it will be near impossible to drive nicley, 4.11 or 4.56's for that combo are needed to get maximum go.

the 4v's should have the tounges installed to get your combo making power sooner especially if it is street driven this will get you off the line faster even with moderate gearing and without the need to pull 7500rpm all the time.

the weiand xcellerator is not suitable for this combo the best manifolds are the funnelweb and the tfc if money allows, be warned the funnel webs can have port misalignment issues and will cost u extra to get fixed so the tfc is the best bet.

the 750 vac wont do u need a tricked 750dp as a minimum, best if it is converted to annular discharge, your other option is a barry grant gold claw which is far superior in all aspects.

i know i have listed big name big price parts but your talking about a $10,000-15,000 motor if done properly.


ok a quick review it is very possible and on pump fuel but it must be done correctly not based on what some backyard botch engine builder told you.

you can make 500fwhp on 98 octane and more if u run avgas and bigger compression.
 

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heres some more info.I'd fill the block to strengthen it at this power level.another good point made as stroking.you mention 5.7 eagle rods,are they 5.778 cleveland specific Eagles or 5.7 chev 2.1 journal size sbc rods.If you have the chev rods i would definately consider stroking.the extra swept volume will enhance your comp ratio as well.
 

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TyreToaster said:
ok cast iron heads will be very hard to tune at 10.5 to 1 , with alloy heads maximum you shold go is 10.5 u can get as high as 10.8 on 98 octane but a bad batch and your car is gona start pinging so as a rule you should allow for a margin of error.

If you want to make more power then u may as well go for 11.5 to 1 -12.0 to 1 (avgas) a cam in the 246 range will work quiet well on 98 octane at 10 to 1 but anything bigger needs more compression.
Just a small correction, I run alloys and run 11.2:1 on 98 octane fuel without an issue. If you want to go bigger comp and retain pump fuel without a huge cam? Alloy is the way to go.

Achieving beyond 500hp with alloy heads is relatively easy also. It's all money though. Better when the $ aint yours. ;)

With cast iron heads, I found 10.5:1 is the limit with an F246 type cam. I used to run 2V closed chambers @ 10.5:1.

Brenden
 

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Hes got 4vs so forget what comp u used as a guide. Bigger por t lazier port so the cylinder builds less low end pressure and isnt prone to detination like 2vs are. Yes port tongues will be better and a F246 isnt a big cam.. I used the f256 in alot of builds with 4vs on 11.5.1 on ulti 98 and have no problems with ping or bearing wear.
 

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Discussion Starter #15
Thanks for all the info, will go back to drawing board
and look over some things with this combo and all your suggestions.
Have thought about going for a funnel web with port tongues.
I havn't got the rods yet but about to order shortly,
The rods are the 5.778 cleveland eagles but may go for 6" chev rods.
Would anyone suggest going for well preped 302 cleveland rods for this engine?

Further input always welcome
 

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i always seem to get misunderstood dont know if its my typing or just me but what i was actually saying was i suggest these ratios to avoid complications should he get a bad batch of fuel or be forced to use standard lrp or unleaded, this way the car could still be driven without too many problems.

i wasnt quoting maximum figures as there are too many factors influencing the individual motor.
 

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Whats the max rpm you can get out of 302 rods, that are well preped etc? For the cost to prep them is it cheaper and better to go somthing like Eagle H beam for around $800

What are brands are there and what costs roughly?
 

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arp bolts $120
resizing rods $90
shot peening $120

new h beams from vpw for example $650 ready to go in
 
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