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MatthewXD302c

302 Cleveland Build

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Hey fellas,

 

I have a 302c waiting to be done up with some bells and whistle, what should be done to give it some power? Not willing to spend a whole lot, maximum 4k. 

 

I was thinking on putting a dominator 3500 high stall, 465 holley carby, edelbrock performance intake and a new exhaust system from the extractors. Is that a good start or am I wasting my money?

Any advice will be great! 

 

Cheers

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4k is a waste purely on hop-ups for a 302. That said, you can spend up on them now if you plan go to 351 later.

I'm not one of those folks who straight away says "302s are dogs, don't bother, etc" because I have one in my wagon. My reasoning was that it was cheap, already rebuilt engine, and it could go in front of a 6-cyl driveline. I run a 6-cyl T5 in mine.

It all depends on what you're doing to it. If you're rebuilding, 4k will be soaked up very quickly in machining and new engine parts, etc.

If your current engine is healthy, money is best spent on the top-end. Get the heads done up with upgraded valve springs, hardened seats, 3-angle valve job, press-on stem seals, shave to get up to 10:1 comp, tidy up the ports to take out dags and ridges. Not including the ports, which I did myself, this whole job cost me about $1400 with parts. Have a look in my thread (gergwagon revamp) to see what I did to my ports.

Don't waste money on an inlet manifold. The only advantage would be weight. The standard iron 4-barrel clevo one is good unit, and would be more than adequate on a 302. The only consideration would be if you have the choked-down (funnel) one that came with the 302, the earlier 4-hole one or the one with 2 open plenums. The last one is most desirable. Mine was the choked one but my brother machined it out to open.

The bottom end, if in good order, will handle decent rpm stock. The short-stroke 302 will sit on 6500 rpm all day, and clevo rods are so beefy that you don't even need to think about them.

3500 stall is pretty high for a street car, might get a bit annoying on the freeway. I'd say go more like 2500, or keep it stock. I assume you're using a C4, in which case you should shift kit it to help it live longer and drive nicer.

Diff should be 28-spline limo. Mine will only be 25 as it's a cruiser and I don't drag race or do burnouts. Plenty of diff gears available to wake it up: 3.27, 3.45, 3.77, 4.11 which is the reason why I advise not to go too high in the stall speed. Depends if you can build your own diff. If not, bolting in a XG ute diff would give you 3.27 but probably open centre. Going up in ratio plus too high a stall would make it unbearable on the freeway. High stall will also cook your gearbox if you run it hard.

Camshafts are chosen on rpm range, so keep in mind that when you're choosing a clevo one, they're quoting the power band on a 351. In a 302, a good rule-of-thumb is to add 500 rpm to that figure. On an auto, you could go with an LSA a bit narrower, say 110-108 so you're in the meat of the torque curve when coming off stall. Choose a cam that's not too much above 0.500" lift as you don't want to stress the rockers too much. I know of a Crow cam that's around 224/224 @ 0.050", 108 LSA, and 0.507" lift that would be a good little cam for your setup.

If you want to use roller rockers, get good ones. Cheapies are worse than using stock rockers. Think about if you want to go with 7/16" studs when getting the heads machined. Clevos aren't cheap to do because of the angles involved. There are bolt-on 5/16" ones from Scorpion or Yella Terra for around $600. You'll probably need pushrods too.

If you keep the stock rockers, run a high zinc oil or moly additive.

Try and find a second hand set of extractors, as new ones are pricey. Mine were $150, new ones are up around $800.

A 600 Holley should do you for carby. 465 will be too small. Reco ones are getting hard to find as carby shops are all closing down now. New ones are pricey too. Allow $500 for that.

So... Budget:

Heads $1500
Cam/lifters $500
Roller rockers/pushrods $700 (optional)
Extractors $800 ($200 s/hand)
Carby $500
Diff rebuild $1000
Shift kit $200 (?)

It's all starting to add up!

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what do you intend to use the car for? 

 

i agree with gerg, and chestnut for that matter.. when i had a 302 clevo, i bought a 351 crank and rods, and the head joint did a trade on My 302 heads for 351 recos for bugger all extra, these days most head mobs can relieve the chambers of the 302 head easy for 351 conversion. 

 

if i was on a budget though i'd keep it a 302, and depending how worn, pretty much do what Chestnutxe does, new rings and bearings(getting crank and oil pump checked by reco machinist, could take block in just as easy also)

 

new timing chain, cam and lifters, seals rings and bearings, reco the worn out dizzy, new leads(good ones)  keep the thermoquad if it works(they are great when they work) 2.5" single exhaust from the manifolds back(cant see them being a restriction on a 302) you'll probably still see most of the $4000 gone especially if you paying mechanics for any of it.. get it dyno tuned by someone who knows what they are doing for $500 and you'll get more from that than most other mods. 


just get in your head that it's a dinosaur V8.. a V6 camry will be quicker if you are racing..  

enjoy the V8 sound and cruise it in My opinion .. it will sound fast if you arn't next to anything new to visualise the slowness(like My gemini wagon, seems fast.. almost any new car will keep up with it if they wanted to)

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My XD many moons ago had a stock 302c, 600 Holley, headers and a std stall C4 with 2.92 gears.
The best bang for buck was the 3:45 XG xr6 ute diff, made a good improvement and could smoke both wheels.




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14 hours ago, NZXD said:

My XD many moons ago had a stock 302c, 600 Holley, headers and a std stall C4 with 2.92 gears.
The best bang for buck was the 3:45 XG xr6 ute diff, made a good improvement and could smoke both wheels.
 

 

revs at 100kmh would be about 2850 ish with 3.45 ratio.. 

so depends what sort of driving/cruising you do and whether you can live with the extra noise/fuel use

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revs at 100kmh would be about 2850 ish with 3.45 ratio.. 
so depends what sort of driving/cruising you do and whether you can live with the extra noise/fuel use

Yeah spot on there.


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Ok, thanks everyone for the responses, I really appreciate it but I have now made a decision and want your input.

 

What cam and lifter kit do you guys recommend?

Would a stage 2 shift kit from Ebay work fine?

Which rings and bearings rebuilt kit should I get?

What timing chain should I go for?

I need to get a new carby (looking at a 600 holley) unless I can get my thermoquad refurbished since it struggles to keep up.

2500 hi stall.

New diff gears recommendation or should I put in an xg diff?

What exhaust system should I go for? Any recommended manufacturers.

A good dyno tuning shop in western suburbs of victoria if anyone has any recommendations. 

 

I want to use the car to cruise around on a Sunday and chop a few of my mates 4 cylinders lol. I want it to sound nice with a lumpy idle.

 

Any changes you guys would recommend let me know since I'm not mechanically minded and any help would be great.

 

 

 

 

 

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11 hours ago, deankdx said:

what 4cyl cars do your mates have? some are damn quick

 

 

just sayin

 

Sorry I meant 6cly,

 

Ones a done up nf fairlane xr6 mock up and ones a stock el,

got chopped by both badly.

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i've been in a manual HYPONL concord NL fairlane that was quick, that runs low 14 second quarters from memory.. (XY GT speed)
 

My fresh reco stock 351 got chopped (car length to 100kmh) by an auto EL falcon that was near new back in the day .. flat 16 second 1/4 mile time..

keep it stock, "cruiser"  buy a manual mitsubishi 380  and chop V8 commodores 

 

 

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11 hours ago, deankdx said:

i've been in a manual HYPONL concord NL fairlane that was quick, that runs low 14 second quarters from memory.. (XY GT speed)
 

My fresh reco stock 351 got chopped (car length to 100kmh) by an auto EL falcon that was near new back in the day .. flat 16 second 1/4 mile time..

keep it stock, "cruiser"  buy a manual mitsubishi 380  and chop V8 commodores 

 

 

Alright then haha so I have no hope, I just want the thing to get up and go and to sound good, are the mods listed above a good start?

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if you are making it go fast to race your mates, you'll need to spend money you don't need for cruising.. probably $6000+

 

if you want to race your mates, buy a fast car, but you can't race on the streets legally anyway..  or do a 13s for $1300 project Like Scotty  from street machine did years ago

 

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11 hours ago, deankdx said:

if you are making it go fast to race your mates, you'll need to spend money you don't need for cruising.. probably $6000+

 

if you want to race your mates, buy a fast car, but you can't race on the streets legally anyway..  or do a 13s for $1300 project Like Scotty  from street machine did years ago

 

Yeah nah not willing to spend that much on the old girl right now, I'm on 1st year apprenticeship wages lol, still need to respray her and do the interior, also want to put 19" globes.

So I just want her to have a lumpy idle, and to sound nice. And obviously drive nicely also. What should I get done?

 

Rings and bearings?

New cam and lift?

600 carby or should I refurbish the thermoquad?

New exhaust system?

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i'll bet the timing chain is worn.. to replace that, you're in the engine enough you could change the cam to a lumpier one(a lumpier idling cam will make a 302 even more gutless on take off)

if it was Me, i'd probably change the timing chain and get a dyno tune.. and call it done. 

 

if you want it to idle lumpy it's going to be slower on take off with a bigger cam..,

 

dyno tuner may be able to get the carby working(they are equivalently bigger than a 600 holley not a restriction)
a 2.5" exhaust will make it sound nice with a straight through muffler.  keep the manifolds, be cheaper and they will be fine.


that will probably cost best part of $1000- $1500 alone

 

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11 hours ago, deankdx said:

personally, just drive it.. 
keep a look out for someone selling a 351 etc cheap second hand.. playing cars while an apprentice will just mean you'll be walking more.. keep it on the road

Ok cool, what cam do you recommend I want it lumpy, dont care if it slows the launch down, I figured from your other post that I'll have to spend a heap tone to catch up with my mates. 

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i couldn't tell you about cam for lopey idle, but what i'd do is contact CROW CAMS and ask them if they have one or will make one that idles like a beast on a stock engine..

Marks XD ute idles awesome.. @XTREME KARTS XF
its stuffed lol.. sounds like that because it's down on compression on a couple of cyls, blown head gaskets

has twin exhausts no balance pipe. 

 

 

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11 hours ago, deankdx said:

 

i couldn't tell you about cam for lopey idle, but what i'd do is contact CROW CAMS and ask them if they have one or will make one that idles like a beast on a stock engine..

Marks XD ute idles awesome.. @XTREME KARTS XF
its stuffed lol.. 

has twin exhausts no balance pipe. 

 

 

Ok mate I really appreciate your help, I'll send an update once the cars all done, I might make a couple YouTube videos on the build. And yeah that thing sounds good.

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definitelty take photos, and videos of anything you do, do a walk around. start a youtube channel. 

always good to go back and look at what you've done. and to share issues and fault finding. plus entertain us also

 

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11 hours ago, deankdx said:

definitelty take photos, and videos of anything you do, do a walk around. start a youtube channel. 

always good to go back and look at what you've done. and to share issues and fault finding. plus entertain us also

 

I definetly will start the YouTube channel.

Just another question.

Where do you recommend to get the exhaust system from? Does it have to be custom fabricated or can I buy pre made ones? And what extractors do you recommend?

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