4- barrel for a 306, check specs & comment

[Caprimaniac]

Hi. I'm rebuilding a long rod 306 "economy".
I thought getting an inlet + carb for this enginge, but have no experience on 4- barrel carbs (only webers). Engine should be a little de-tuned compared to the current 347 solid roller, a little more street friendly, but still racey. will shift at 7000- 7500.

Let's see:
- 1982 block, 030 over & crank
- Eagle SIR 5.4" rods and KB 746 pop-up pistons
- Solid cam, for instance comp 31-366 or 31- 335
- Some kind of cheepo aluminium heads. Not sure what yet. found RHS heads @ 439$ each complete, but turns out a misprint... Another option is to upgrade my Vic Jr's on the 347 to something even "better" and put them on the 306.
- Weiand X-CELerator single plane manifold
- Holley 650 DP w/ mech. secondaries (4150 street HP series, HLY-O-82651), Proform ditto (PRO-67199) or AED HO series 650 (AED-650HO)

This inlet seems to do what I need it to do and even fit under the hood. Problem is the carb. I guess 650 cfm is enough for a 306 @ 7000 rpm?
Have some of you fitted any of these carbs to a 302 and found it to be "correct enough" jetted to suit this application? The less fiddle to fin dcorrects jets etc, the better. I also wonder what kind of adjustment can be done to these carbs without changing the jet. Can the mech. secondaries be adjusted?
Ok, now I feel a little guilty... Will check the websites to look at specs & tunability of these carbs...

Thank you

RS

[Rick Parker]

You may find the Weiand X-CELerator single plane manifold is a little too small (plenum & ports) for displacement and intended RPM. Single plane will work and is required but look towards Victor Jr from Edelbrock. A well done 650 DP will work very well.

[blykins]

There's really not a good "cheap" aluminum head. There are Procomps, but by the time you fixed all the things wrong with them, you could buy a nice set of heads.

A 210cc Vic Jr. head on a 306ci engine would make it pretty doggy on the street, but if you're on the track a lot with a steeper rearend gear, it would probably be ok. A nice set of AFR heads for the 347 would really make some power.

As Rick mentioned, you're better off with a Vic Jr. or Super Victor intake for the 306.

As for the carb, it will be hard to say how close an off-the-shelf piece will be out of the box.

If you're willing to pay a little more for some custom work, I can provide a Quick Fuel carburetor that has been custom assembled to fit your engine/application. It will be built from the ground up and should be extremely close to the tune that you will need. My gut tells me a 650 would be the right size.

If this is going to be on the race track a lot, there are better choices for a camshaft as well.

[Caprimaniac]

Thank you all so far. 650 & a "more ram" intake it will be. I will have to check heigth of the components. But maybe someone can give me a guildine here. Have 48 IDF on Inglese manifold + K&N filters (oval type). Will 4- barrel + Vic jr. w/ low profile air cleaner be of the same height? I think I measured current setup as 10" high from base of manifold to top of cleaners.

So, AFR's will do the 347 something good? Hmm. I will look closer. But exactly what will they do?

- 205 AFR's 291 VS 296 cfm @ 0,6 lift, a little more difference at the exhaust...

- 60 VS 58 cc chabers Makes compression 10.8 instead of 10.5

- Both designs have raised exhaust ports.


I don't know. The Vic jr's should take it to 500+ Hp. Is there really alot to gain?

rS

[blykins]

A Victor Jr. intake is 5.5" tall by itself, so you'll be up over the 10" by a bit.

I wouldn't pay much attention to advertised flow numbers; they can be tricky to sort through sometimes...plus most of the heads never flow what the manufacturer says they do. The AFR 205's would probably be 20cfm over the Victor Jr's. Also, peak flow numbers aren't everything....the average flow numbers (low and mid lift performance) means a lot too. Adding more cfm while keeping the CSA the same or lower makes for a good performing head.

[blykins]

BTW, if the heads flow what the manufacturers say (grain of salt there) AFR says that their heads will flow about 308cfm @ .600". The Vic Jr's are about 280-285 at that lift usually.

[vector1]

i like to look at reference material for information so i whipped out bulding ford short-track power and on the back is another book called 5.0l ford dyno tests you might want to look at, over 2000 dyno pulls.

[Caprimaniac]

Yes, Vector- seems like a nice read.

AFR say 308 @.600, but in the tests I've read so far said 296 and 300, but anyway.

What makes the AFR flow more than a vic jr? The valves are not moved around like a Twisted wedge. The ports are smaller than on the Vic's, but the inlet valves are a bit larger. Shape of the ports/ channels might also be "better" on the AFR's.

Lot's of people say AFR's work good for them. And that's fine. But Brent (or anyone); exactly why would a move from Vic jr's to AFR's do the trick for the 347? If you don't look at the flow numbers, then what's left is the wide exhaust bolt pattern which will do some good...

I've been looking into this alot. Options I have been considering are: Victors. Because of raised inlet ports (need spacers, but that's OK): Will cost quite alot to prepare & complete a set of those. Twisted wedge R 206: Have to change the pistons, as I have understood(?).

Anything in height between a Vic jr and a x-celerator inlet?

rs

[blykins]

The Victor Jr's have always been towards the middle of the pack for a good performance out of the box head. The ones that are towards the top (without going to a Cleveland style head) are the AFR heads, the TW-R, TFS High Port, etc. However, as you stated, the Twisted heads require a piston change.

You posed a situation earlier where you would use the Vic Jr's for the 306 and you would buy a higher end head for the AFR....that's where this idea stemmed from. The AFR 185/205 head would outperform the Vic Jr heads without really breaking the bank.

I would imagine that it is the shape of the port on the AFR. As you said, it's a smaller volume that flows exceptionally high. Low lift and mid lift numbers are high as well. I can't really say exactly what it is, I've never seen a port cross-section between the two.

[YerDugliness]

Originally Posted by blykins

The ones that are towards the top (without going to a Cleveland style head).....

This may be a bit OT, but, Brent, would you mind expanding on your reference to the Cleveland head? I've been a fan of the 335 (and 385) series Ford engines ever since I had a 351C-2V in a 1972 full size Ford Custom 500 that would walk away from SBC's with 4V carbs.....my dream "replacement" engine for my Cobra is an 8.2" deck height "clevor". I know, there aren't a whole lot of good domestic intakes for that clevor (Edelbrock makes one in an RPM model, but no Air-Gap that I know of, and no single plane models, either). The Aussies are WAAY ahead of us on the canted-valve heads, having had them for so much longer than we did.

My theory is that the Cleveland heads flow better b/c as the canted valve is opened by the cam it moves away from the cylinder wall, thereby essentially "unshrouding" the valve head and increasing the flow compared to a standard head.

What do you recommend for a SBF "clevor"......carbureted, of course!

Cheers from Doug

[blykins]

The Cleveland heads make a lot of power. Even the old 4V style heads can be ported to really cut the mustard.

If you chose to go with the old iron stuff, you can make a 4V head flow about 310-320cfm. Then you have a choice of 4V intakes: the Holley Strip Dominator, the Edelbrock Torker, or you can even adapt one of the new CHI intakes. The 3V intake has a port dimension that you can easily fit inside of a 4V port.

If you go new aluminum, the CHI 3V heads will absolutely make the power. AFD also makes some very nice aluminum heads for the Cleveland. Both of these companies are Aussie companies.

You also have a choice between the various Yates heads. Most of those have really big port volumes, so it's not good for a small cubic inch engine...plus the chambers are really small, so static compression ratios would be high.

There are various intakes available for each scenario.

If a budget wasn't a factor, a 351W based Dart block with a large stroke rotating assembly (445-460 cubic inches) with a set of CHI 3V heads, a single plane CHI intake, and a mild street roller cam would be close to or slightly above 700hp.

[Caprimaniac]

OK, Brent: I see you point here. After looking at the flow charts, the AFR's look like they're a step up from the Vic Jr's. and the Vic's seems like an OK choice for the 306 build up.

Agree on the Cleveland heads. Everyone talk about the Aussie heads, but what about the Edelbrock, and even more, the Trick flow Cleveland heads? Let's take a Trick flow 190cc set of heads; they will outperform ANY? set of windsor type head, I'd guess. Even a set of 220- 225 AFR's? And also- is there a set of spacers available to use a Windsor inlet manifold on the Cleveland heads?

Anyway; I just popped in to say I have a suggestion to mention; one solution to make it a little more easy to adapt larger primary exhaust header tubes to the Vic. Jr.'s. By using a smaller diameter bolt & nut, it makes more room for the tubes. I fond ARP 100-1401 which have 5/16 diameter on the outside while still 3/8" into the heads.

Anyone else tried this?

RS

[blykins]

The CHI and AFD heads are basically the cat's meow on Cleveland heads. I'm not 100% sure about the TFS heads, but the Edelbrock heads are 2V style heads. Flow rates for either are in the 270-280 range from what I've seen. The 3V CHI heads will flow about 340cfm.

There are intakes available for about every situation....8.2" Clevor, 9.2" Clevor (standard 351C deck height), 9.5" Clevor, etc.

The header bolts that you mentioned are commonly used. You can also use an allen (hex) head bolt that will give you more room.

[Caprimaniac]

Ok, I see the difference there on the Cleveland heads, clearly.

Why do I come ine here now? Wanna get rid of frustration!
After spending hours looking at different cylinder heads, AFR closely, I just canno seem to find something that suits me well... The AFR's either come fully assmebled, with wrong valve springs, retainers, locks and rocker studs (but clearly a gud buy at 1800 with CNC machined ports, bowls & chamber) or bare unported and unfinnished... If they only had have been ready ported & with finished valve seats!

The "correct" out of the box part numbers are hard to come by, sometimes. A note on the 205 AFR's also say "will not accept rail rockers" while the Jesel part number KSS-516060 says it fits all AFR up the the 225 heads. (It might be the spring diameter that cause this?)

[blykins]

Which cam are you going to run? Roller or flat tappet? The heads are available with all sorts of valve spring combinations.

A rail rocker is considered a pedestal mount rocker arm, like the factory 5.0 engines had. The rocker arm is just bolted/torqued down to the head, without the use of a guideplate and rocker stud.

I just built a 347 a few months back with AFR 185cc heads and a very mild solid roller cam that made 490hp with an undersized carburetor. The AFR heads are very good heads. I hate to go over about 500hp without a lot of block prep (main girdle, studs, etc) because the biggest weakness here is the factory block.

[Keithc8]

It sounds like to me that all of the heads you are talking about is to much head for this engine. It will be a real dog down low. Unless you plan on running 12 to 1 compression and do not care what the engine does below 4000 rpms you can go with any of these heads. There are to many wedge heads that will do the job and I would not do the canted valve 351C heads because it is a pane in the ass to do.
You could do a nice CNC ported AFR 185 or our KC Signature 195 head and have a much better engine. You will have to turn the engine up to get a 302 to make 500HP. It takes a complete package and most people over carb and cylinder head their enignes.
We make 750HP with original 428CJ cast iron heads ported on a 11 to 1 440C.I FE 428CJ engine with a Dove single plane intake and 735 carburetor. The heads only flow about 340 on the intake and 260 on the exhaust. Let us know if we can help.

Thanks, Keith

[Caprimaniac]

Well; I have been into this thought as well, and so have Brent by suggesting AFR 185 heads. But, by that you're also asying my current Vic Jr's are too large? 205cc inlet, isn't it? And 300 fcfm @ .600? The engine does not feel lazy at the bottom as is, that's for sure. Could have a bit more at around 4000, but that might be due to 4 degrees retarded cam.

This thread has, as always, come out of proportions. But just let me introduce this suggestion for my track/ road race 347 (1070 kg's w/ driver, fuel, race ready):

AFR 205 and this cam:
SPEC CARD# 18788410 SPEC CARD INQUIRY BY SPEC CARD NO
PART # 31-000-8 CAMSHAFT, FS FORD 289-302 HR/SR
CORE C99 CAMSHAFT BLANK, DUMMY OVERRIDE CORE
GRIND # FS 4135 /4139 SR110.0
DURATION @ .050 INTAKE 268 ROCKER ARM RATIO
VALVE ADJ INTAKE .020 DURATION @ .050 EXHAUST 274 INTAKE 1.60
VALVE ADJ EXHAUST .020 LOBE LIFT INTAKE .4360 EXHAUST 1.60
VALVE LIFT INTAKE .697 LOBE LIFT EXHAUST .4360
VALVE LIFT EXHAUST .697 LOBE SEPARATION 110.0
DURATION .020 INTAKE C/L 106.0
TAPPET LIFT INTAKE 299 ADVANCE 4
TAPPET LIFT EXHAUST 305 HYDRAULIC
VALVE TIMING .050 OVERHEAD CAM N
VALVE OPEN INTAKE 28 JOURNAL DIAMETER STD .000
VALVE OPEN EXHAUST 71 RECOMMEND VALVE SPRINGS
VALVE CLOSED INTAKE 60 DEPARTMENT R
VALVE CLOSED EXHAUST 23 SPC INSTR FOR CUSTOMER



- Comp cams Elite roller lifters (as my old rollers have no oiling to the rollers)
- Jesel shaft mounted rockers
- jesel belt drive.

Makes it 5000$+, and that's insane.

[blykins]

I think those heads would be just fine as long as you kept the rpm's up.

As for the cam, I think it's too much duration at .050" and too much LSA. However, I try to not get into peeing matches on camshaft choices. If you were my customer, I'd send you what you need....but there are too many opinions (many by non-builders/non-racers) on here to get into a good camshaft choice discussion.

Feel free to PM me privately...

If you go solid roller, make sure you buy the billet core...not the cast core.

[Barry_R]

Mixed messages. The short block you describe is very economy oriented and would be well served with any decent bolt on alloy heads beyond the unusable Pro-Comp stuff. You would likely never know the difference between a RHS or an Edelbrock street head at that level - without porting, other things would be holding it back.

The largest AFR head I would use on that would be the 185. We've run those often on 331/347 combos and had them perform really well. On a recent 331 with AFR185s, a hydraulic roller and an Edelbrock dual plane we got right around 400HP/400TQ running an ancient but much modified 715 carb. Fit nicely under a flat hood '68 Mustang. The 306 would be on the good end of the fringe with a similar combination - not quite as crisp due to port volumes with less TQ and similar peak power.