'68 302 4V rebuild

I’ve got a 68 standard model with a 302 4V, auto, P/S, P/B, A/C (inop at the moment). I hadn’t driven it in a while, so I pulled the carb (autolite 4300) and rebuilt it. When I did that, a screw fell out of the bottom of the carb and I didn’t notice it, and you know what happened next! anyway, the damage wasn’t too bad, dinged up the top of 2 pistons and bent one valve, gave me a excuse to pull the motor and give the engine bay a much needed spruce-up. while going through the motor I discovered the main & rod bearings were a little worn, so what the hell, overhaul time.

questions for you guys:
replacing the original ford cam, thinking of putting a little beefier cam in, but don’t really want to do a lot of mods to the engine, and I want to keep it civilized for cruising to the Sonic. Comp cams is recommending # 31-234-3. Here is a link to the specs: https://www.compcams.com/xtreme-energy-212-218-hydraulic-flat-cam-for-ford-221-302.html. any thoughts?

I’m also going to replace the Autolite carb. this thing’s been rebuilt so many times it’s just wore out, I think I’ve helicoiled every hole in the damn thing (well, except for the one…)!
I’m thinking about a Edelbrock AVS2 mod 1901, 500 CFM electric choke. from what I’ve read, they’re a pretty easy swap, and run well out of the box without a lot of tweaking. I’m not opposed to going with a Autolite 4100, or a Holley 4150/4160, but neither are “correct” for the car anyway (it’s not concourse, but is about 95% original), and the Edelbrock seems to be a little easier to set up than the Holley, and more available than the 4100. again, any thoughts?


If you are replacing the camshaft you will need the appropriate lifters and valve springs, retainers, and new keepers. A new set of valve seals too. The cam you selected is appropriate for your usage but the K kit is everything that you need:

Personally I find the Holley is much simpler and easier to tune and produces better performance and more efficiency. Both brands respond poorly to having gas go bad in them so it is important to either use non - ethanol gas or to drive the car at least every thirty days.

If you change the camshaft you will need to have a torque converter matched to the new camshaft in order to maintain idle quality and to avoid stalling when idling in gear. Hughes is one good brand available from various sources like Summit Racing. You need at least 2000 RPM stall speed with that camshaft.

This Lunati 10350700 is in my '68 302 and idles like a lamb. Like Comp’s, it will need the matching 73084K1 spring-retainer-keeper kit. I can vouch for it being a stealthy one that delivers. I get 17.5 in Hg idle vacuum at 750.

The one below the 10350700, the '701, is closer to the Comp number you have picked out. The milder 10350700 helps my dog-breakfast 8:1 302 to low 15s-high 14s, comfortably on a stock C4 converter.

I’m with Royce on preferring Holleys. A smart shopper tip is to see if Holley has has “refurbished” 80457S carbs available. They’re new carbs returned for various reasons and you save 1/3 off the price. Add a 34-13SA rear metering block kit and you can convert from the standard metering plate.

Is that the “RV” cam? I had bought that one for the first Cougar but never got it installed.

A few years back I did a hidden concours build for a 68 J-code Mustang, we used the stock 4300 carb, zero decked, all iron, a recurved stock distributor and manifolds. Using a N+271H grind, specs below, that car ran STRONG. In fact, my buddies alum head 68 with the Ford stock roller cam, alum top end to include mild Holley alum heads, couldn’t walk away. The cam worked great with stock converter, but as stated, you need springs

Here are the specs, BUT, I would not recommend this cam, I will throw some lobe options instead for a custom cam later. This specific lobe is designed to make noise, crazy, but the idea was to sound like solids. As a builder, I hated it, and assumed we could adjust it out, or use a different lifter. Since then (this was 2009) I learned that the lobes they use are noisy, and they have many like that from comp. However, it’s easy to get pretty close with a custom cam and not much more expensive

Camshaft Specifications: N271H

  • Lobe separation (degrees): 112 (45.5 degrees overlap)
  • Intake Centerline (degrees): 108 (we put it on 105 centerline)
  • Valve Lash: Hydraulic
  • Duration: Intake 266/Exhaust 273
  • Duration @ .050" Lift: Intake 219/Exhaust 226
  • Valve Lift: Intake 0.480/Exhaust 0.475 (1.6 rockers)
  • Lobe Lift: Intake 0.300/Exhaust 0.297

What I would use in the same engine today would be

Custom Comp 5222/5213-13

  • Lobe separation (degrees): 113 (46 degrees overlap)
  • Intake Centerline (degrees): 105
  • Valve Lash: Hydraulic
  • Duration: Intake 268/Exhaust 276
  • Duration @ .050" Lift: Intake 218/Exhaust 226
  • Valve Lift: Intake 0.483/Exhaust 0.481
  • Lobe Lift: Intake 0.302/Exhaust 0.301

The cam would be mild, have a little chop out back, but idle smooth, although much more about the build and driver is required for final choice, the lobes picked would run silent and be happy in a daily driver with full exhaust. I chose these lobes because I know they are quiet, work well in a SBF, and you’d be surprised how easy it is to get a custom cam exactly for your needs. Additionally, Fords tend to like having a little more advertised duration, which sort of drives me away from Voodoos and Xtreme Energy lobes

I agree a Holley is the way to go, and those Lunatis likely will work great, but need to watch compression with the short advertised. Also if you have a good 4300, they run great. The owner of the car eventually got sick of the stock look and went 600 Holley, F4B alum intake, and headers, and he said it made even more power. Something to think about

One last comment, hyd roller cams are pretty slick now, and no worries about break in. Doubles the cam price, but if you don’t eat a cam, it’s often worth the expense

Cougars_R_Grr8 - not sure about the “RV” cam shaft, I just plugged my info into the Comp Cams form and that’s what they recommended

R.B.Phillips - I’ll take a look at the Lunati cams, I appreciate the info

Royce - I was planning on new lifters and all the other pieces, I’m hoping this is the last time I open this engine. I hadn’t thought about the converter, factory rating is 1780-2000 stall, so I may be ok.

I’ve looked some more at the Holley web site, and now I’m confused. according to their charts and formulas a 302 with a 5000 rpm redline it should need about 450 CFM, which is about what the Autolite 4300 is, and that matches what Edelbrock says too. All of the info on there that talks about picking the right size carb says to error on the small size, but they offer very little in the 450-500 range, most are in the 570 and above. R.B.Phillips mentioned a 80457S carb, which is a 600 CFM, is that too much for this engine? would I be better off with a SL-450-VS (450 CFM) or a 0-1848-2 (465 CFM)? I like the looks of the 0-1848-2, but that sucker is $528 compared to the 80457S at $360!

My427stang - you are WAY smarter than me on cams! I’m just looking for something I can cruise to the Sonic on a Friday night, but still get a little thrill out of it if I put my foot in it. I’m going to do a little more research and talk to my machinist before I buy a cam.

My 4300 is just wore out. It runs really well for about a year after a rebuild, then it starts hesitating taking off. I don’t know if it’s just this carb, or me or what, but it’s done it since I bought the car in '78, and it was my daily driver until '99, so I’ve rebuilt that carb at least a dozen times over the years. time to just put it on the shelf and get something new.

I’d love to have a 1848 or 1849 that still sold at a lower price. At one time they did. I might, but the $200+ price for the “refurb” 80457S was too good. It is certainly not too much for my low-compression (i.e., dog-food) 302. I’m even using it on the “big” Weiand Stealth 8020 from circa 2000. A quick advance curve plus vacuum advance, and I have response all over the tach.

The 4300 that was on my '68 J-Code was not an original '68 4300, but a later ~600 CFM one that I traced down to a 460 police application. Until its float got compromised and I took it off, the car was plenty responsive with it, also.

With respect to cams, I’ve used a personal rule over the years that has worked well. Pick the cam whose description sounds “right” or sexy, then drop to the next milder one in the company’s series. It’s how I arrived at the Lunati one I like now. Just a thought.

I don’t use the Holley recommendation. Here’s what I know from experience -

A 600 CFM Vacuum secondary carb is perfect for a 289 / 302.

A 650 CFM vacuum secondary carb is good for a 351.

A 750 CFM vacuum secondary carb is good for a 390 - 428.

Your stock torque converter won’t be good enough so don’t even imagine that it can stay with that camshaft. You will need the bottom of the line converter from One of the converter companies. Again I prefer Hughes but you can spend a lot more or a little less and get something that would work.

I wouldn’t jump so fast on “you need a different converter”

The stock J code cam was installed way late, and although it had wide lobe centers, the advertised duration was higher, so it had close to the same overlap as the cams I mentioned and likely more than the Lunati’s. A 268 intake on 106 with 46 degrees overlap is easier to idle and higher vacuum than a 272 advertised on 114 ICL with 40 degrees overlap.

The rule big cam = bigger converter is true, but has to be applied to the situation. Just to be clear though, not guessing, I built this combo and it was mellow and happy as can be

I am going to say right now that my statement is not a generalization. The cam he has selected needs an aftermarket converter. Not a 8” 5000 RPM converter but a cheapie slightly looser than stock converter.

Royce, and I still say that is incorrect, without hesitation

That cam has 42 degrees of overlap,is even milder than I recommended, on top of that an earlier and shorter intake lobe at 256 degrees on 105, milder in terms of idle and more vacuum than even the stock J-code cam, it is an absolute baby, and will work fine with a stock converter. In fact, I am not sure it would even outpower the J-code up top, but would likely have more torque. I can’t hold a candle to you on Ford part numbers and certainly not on Cougars specifically, but I promise this cam doesn’t need a converter

The issue of course is if he buys a mild performance converter, it won’t prove anything either way because it will be happy either way

We will have to agree to disagree then.

Fair enough, hope everyone is healthy in your neck of the woods.

My427stang, I nearly chose the replica of the old C9OZ (-6250-C) Ford Muscle Parts hydraulic cam - 290 advertised, 218 to 220 @.050 depending whether you get Melling’s or Lunatis, and only .465 lift with 1.6s. But it has 113 LSA (Lunati version) or 115 (Melling-Howard version). It would be fun to put one together sometime.

I’d also look into getting GT-40 heads as well. They aren’t too unreasonable. I’m running an Edelbrock 500 cfm AVS2 plus a performer 289 intake.

I’m not sure if the camshaft is Edelbrock or the GT-40 one.

(I really should pull the intake and try to find out. The GT-40 camshaft might or might not be a roller.)

The effect you get from those redesigned primaries is very snappy & 500 cfm is all you need for the 302. I called Edelbrock before ordering and they insisted that there was no benefit to the 650 cfm unit unless it was stroked out to 347 cubic inches or for a bigger engine.

I also just upgraded to the latest greatest Petronix instead of points and a 12 volt ignition coil. (Gotta match the rest of the electronic system after all)

It’s loads of fun to drive but you’ll still probably need to run premium gas.

I agree, although nowadays I like to use all the lift I can (my hyd roller mild FEs are .600-.630 lift), we have seen that the Fords like slow ramps. Not only a spring control and noise thing, they make more power. As you see though, they have to spread the centers a bit on those cams to kep vacuum in check. I’d like to see that Lunati version on a 104 centerline with 10:1 compression in a hot little 306. Modern lobes will make more power, but that little cam with 66 degrees overlap would sound nasty and be fuun

It’s wild how cams have changed, CJ cams, 270/280, low lift, 114 LSA and ICL (all those are rounded), J code cams were actually more intake duration than exhaust, something you don’t see anymore, also spread centers and installed late, and they ran really good. I don’t like doing the late ICL, I think there is free cylinder fill and swept compression there if you go earlier, especially on short stroke street motors, but as I put more on the dyno and use them for different things, I am spreading centers more and more

My last 2 concours-hidden CJ strokers I did were 290’s advertised and 114 LSA (idled at 15 and 16 inches vacuum) difference between the two were one had 1 mm rings and a little more vacuum. The two going on the dyno on the 14th are leaning toward wide too, a Tunnel Wedge 457 destined for a “dollar car” original Mustang racer, and it’s going to be lumpy, but on 112 LSA, and a Trick Flow alum headed 461is spread to 113 and I am hoping to tickle about 575 HP on pump gas with vacuum

In the end though, I will say this, and not that you are inferring a cam is the way to make power, but as a public service announcement… fast guys make power with heads, slow guys make power with cams…silly generalization and of course everything needs ot be right, but it’s amazing the power a set of well-matched AFRs will make on a small block, even with a mild cam, however, cam it up snotty with stock heads…it’s all sound

Of the two going on the pump, the Trick Flow 461 will have 8 degrees less intake lobe (.050), less compression, an RPM intake, and a single 780 vac sec. The Tunnel Wedge has CnC ported CJ heads, more compression a Ford Tunnel Wedge intake, and the bigger cam. I hope they pull the same HP, but my gut tells me the single 4 is going to beat up on the Tunnel Wedge :slight_smile:

Just some food for thought…why not a crate engine? I think you would be surprised in cost savings compared to machine shop costs etc…

Original poster may want to keep his 1968-stamped production block. Some garage talked my previous owner into a new long block; one of my disappointments I had to deal with when buying the car.

Some people also like the heavier pre-1981 302 cranks that required less external balance, too. A superfluous argument akin to arguing about single-malt Scotches, sure, but there it is. Any new crate motor will be the “5.0” era 50 in-oz stuff (not that that stopped bus loads of worthies from running 12s with them au naturel like I did, or, 10s or high 9s with ***loads of N2O).

ATK and Blueprint both offer J-Code equivalent engines complete to carb for $3100; but they’re crappy heads, weenie valvetrain. Not low quality, just weenie. But certainly an instant solution!