67 383 rebuild suggestions

[swisherred]

I would like to look into rebuilding my 67 newport 383 next year but would like suggestions on what to have done. The car has just over 100k. Stock 2bbl motor with 4bbl added. 727 w/ 2:76 gears. I would like to increase the cam a little...thinking the voodoo 262/268 cam. This would be for a fun weekend driver leaning towards highway cruising for long drives but still with some fun torque.
What work should I have done to the drive line to add a bit more fun but still run on pump gas and get reasonable mileage? Currently the engine has no knocks or major issues...

 

[detmatt]

I’d do a leak down test before making any total rebuild decisions. I treated the 440 in my Imp to a fresh set of iron heads with bigger exhaust valves, a new cam and timing chain set at about 140k miles. The rotating assembly just needed a rear main seal at the time. Don’t go too crazy with a cam, you’ll end up regretting it.

 

[swisherred]

I’d do a leak down test before making any total rebuild decisions. I treated the 440 in my Imp to a fresh set of iron heads with bigger exhaust valves, a new cam and timing chain set at about 140k miles. The rotating assembly just needed a rear main seal at the time. Don’t go too crazy with a cam, you’ll end up regretting it.

I was thinking the voodoo cam because it was designed to utilize the valve train better than stock to actually use the hp flowing through them and out the exhaust...not to generate more...just not waste it. I'm getting ready to change the timing chain now and of course that part touches another dirty part....and that must be cleaned....but it touches yet another dirty part that needs to be cleaned so of course I need a total engine rebuild to replace my timing chain...lol.

 

[detmatt]

I was thinking the voodoo cam because it was designed to utilize the valve train better than stock to actually use the hp flowing through them and out the exhaust...not to generate more...just not waste it. I'm getting ready to change the timing chain now and of course that part touches another dirty part....and that must be cleaned....but it touches yet another dirty part that needs to be cleaned so of course I need a total engine rebuild to replace my timing chain...lol.

We all know how that goes!

 

[swisherred]

Seriously though...thinking leak down and compression test first...to decide if the bottom end is ok or not....then refresh the heads with new seats and grind..new pushrods (previously bent and straightened from last owner)...new dual exhaust and cam and possibly ignition upgrade. Service the lifters and rockers. Make sure the valve guides aren't worn too much.

 

[detmatt]

Previously bent pushrods should definitely be replaced.

 

[413]

There is free torque in changing the rear end gears. 2.76 kill the torque, even 2.94 will improve seat of the pants feel and still cruise great. 3.23 is my favorite. What size rear tires do you have?

 

[swisherred]

There is free torque in changing the rear end gears. 2.76 kill the torque, even 2.94 will improve seat of the pants feel and still cruise great. 3.23 is my favorite. What size rear tires do you have?

205 something 14....can't remember....

 

[Ripinator]

Previously bent pushrods should definitely be replaced.

And springs. . . And retainers / keepers. . .

 

[Davea Lux]

As noted partially above, if you are going to do heads and want them to live on moonshine blend gas, be sure to install bronze valve guide inserts and hard seats with new valves. Going to a set of the '70 Magnum valve springs and retainers will improve top end performance as will modern light weight tubular push rods. For street use a factory configured magnum cam is probably a good choice. You will need to convert to a 4BBL setup with any performance cam. You probably also have a single exhaust which should be upgraded to duals. This upgrade, if you are looking for better performance needs to be done right with the proper compression ratio and gear set. Involves a lot of work and expense to get it right.

Dave

 

[413]

You would be wise to stay with closed chamber heads. You will give away too much compression with open chamber heads. It would be a losing decision.

Keep the cam smallish for the same reason. A 383 2bbl doesn't have much compression to start with.

 

[Big_John]

IMHO, that's too much cam for what you want.

 

[LocuMob]

HP can grind and valve gear? Dual exhaust if it doesn't have it already. I like 3.23's and up, with a bigger tire in the rear. Use a '68 383 4bbl intake, they flow better.

 

[swisherred]

I currently have a 4bbl on the lower compression 2bbl engine although I haven't dated the intake. I do plan on dual exhaust later. Not sure how much it would be to install valve guides...didn't think it would need them. Any benefit to them? I'm not looking to Jack the hp up high...just give it some more pep while I'm in there...but still keep it very reliable and streetable. Have stock heads...don't know what they are but not really looking to change them.

 

[swisherred]

Mostly this is about freshening up the engine.

 

[LocuMob]

I currently have a 4bbl on the lower compression 2bbl engine although I haven't dated the intake. I do plan on dual exhaust later. Not sure how much it would be to install valve guides...didn't think it would need them. Any benefit to them? I'm not looking to Jack the hp up high...just give it some more pep while I'm in there...but still keep it very reliable and streetable. Have stock heads...don't know what they are but not really looking to change them.

The guides are for dealing with today's fuel and ethanol added to it. If you go through the heads and freshen them up, and replace the guides and seals, you should never have to touch them again. If the heads are be off for gasket replacement, it's a no-brainer.

 

[PurpleBeeper]

Well, I have some different opinions vs. many of the posts above.
1. The gear ratio change to something like 3.23 (& corresponding speedometer gear in transmission) would probably help the most for more "pep".....but you asked about the engine.
2. I think your cam choice is just fine, even with 2.76 gears.
3. Install hardened exhaust valve seats (for unleaded gas) and new valve guides (so you don't burn oil) and keep those closed chamber heads. If you have some extra cash, maybe have the exhaust valve throats enlarged and go to the larger '68+ exhaust valves.
4. Replace timing chain & oil pump while you're in there + inspect the oil pump drive gear.
5. Your stock valve spring retainers (steel) should be fine, but install a new set of valve springs as recommended by your cam manufacturer.
6. I like electronic ignition, but you don't "need" it. Do check your distributor bushing "wobble". Your point dwell can fluctuate A LOT once the distributor housing bushings start to wear out allowing the center shaft to move back/forth.
7. You will likely need to bore the cylinders & get new pistons, so go with flat top pistons (not dished 383 2-barrel pistons)...but MAKE SURE they don't stick up too far & make contact with your closed-chamber heads.
8. Definitely add dual exhaust when you have the time/money.
9. Lastly, if you don't mind a little under hood noise, install an "open element" air cleaner with a K&N air filter, or just find a 1" taller-than-stock K&N so your air cleaner lid doesn't seal to the base (basically making it an open element air cleaner)
HOPE THIS HELPS!

 

[swisherred]

So assuming I just have the heads done right now...guides seats springs...any thoughts on what I'm looking at cost wise for that? I can't afford the bottom end right now but I don't think it's going to need it nearly as bad as the heads (unleaded fuel damage). I know it varies from shop to shop...rough guess

 

[Davea Lux]

So assuming I just have the heads done right now...guides seats springs...any thoughts on what I'm looking at cost wise for that? I can't afford the bottom end right now but I don't think it's going to need it nearly as bad as the heads (unleaded fuel damage). I know it varies from shop to shop...rough guess

You are looking at $650 to $800 to do the heads on the West Coast, do not know what it would run on the East Coast. This would not include new springs.

Dave

 

[jct]

I did mine for about 1500 for magaflux, hot tanked, hardened exhaust seats and rebuilt the heads new valves and all that which also included two intake manifolds