BigBlockk Thank you VERY much for all this info and digging up the links

I have a couple of questions
How critical is the quality of the porting as I have never done this before, and I would imagine this is done BEFORE the heads are sent out?

Will a good head shop do the porting?

And last about the manifold, why cant I stick whth my Edelbrock Performer as I will be using the same heads.

The L-82 intake doesnt sound like a problem other than blocking off the EGR port on top but that intake limits me to using a QJ only as there is no bolt pattern for a Holley

Thanks again!
Bob

 

The porting work should really be done after the heads come back from being rebuilt. After all machining is complete you need to get in there and knock off the sharp edges and casting burs. All you are really working with is the first 3/4" to 1" and the last 1/2" to 3/4" of the intake port and all of the exhaust port. On the intake side you gasket match the intake manifold to the heads and smooth out ridges and roughness just upstream of the valves. On the exhaust side the entire port is ground until the casting texture is gone. That's it. As long as you're careful and don't mess up the new valve seats it is really not a big job. I would think just about any head shop would be able to do this kind of work.

I thought you were using the stock '73 intake manifold. If you have an Edelbrock you want to use, by all means. I can't understand why you would want to use a Holley on this engine though.

BigBlockk

Later.....

 

Its just another option... ya never know with me..

Also you recommended a camshaft with about 210 to 216 degrees intake duration (@.050" lift).

The link to Jegs was dead so I searched the site for SBC camshafts and couldnt find anything that small
I think the smallest I found was in the 220's ?

Is the porting difficult? I dont want to screw up the stock heads

Thanks again

 

I just saw that those links are dead. Look at #279-113932.

http://www.jegs.com/webapp/wcs/store...tegoryId=10707

Take a look at #289-85008.

http://www.jegs.com/webapp/wcs/store...tegoryId=10605

Take a look at #500-68300.

http://www.jegs.com/webapp/wcs/store...tegoryId=10605

Sorry about that.

The porting really isn't a big deal.

BigBlockk

Later.....

 

Thanks BigBlockk
A lot of advice here which makes it very difficult for someone with limited knowledge on this subject

Im about ready to take it to a local speed shop and let them do whatever it takes.... I really dont care what it costs but I dont want my Corvette tied up for more than a few days

 

If you don't want it tied up for more than a couple of days, go with the crate motor. If you get a crate engine, you can have it in over the weekend. If you build one, it will take some time.

Plus, if you are anything like me, at least one unexpected event always happens.

 

That is an option as I did mention it in this thread
I am just getting very confused as to what to do because of so many different opinions

My valve guide seals are shot so I thought I would simply buy a set of smaller cc chamber heads and bolt them on and be done with it while gaining a little more HP in the process

This whole matter is honestly begining to stress me out simply because I dont have any real understanding about camshafts and cylinder heads.
I know how things work but I dont understand all the differences such as duration, lift ect:
Right now Im leaning towards replacing the seals and saying screw it

 

I wouldn't just give up. You will regret it later if you already have it apart. Really the only thing that you know need to know with the heads in order to match it with the camshaft is the amount of airflow it has and at what number. Obviously the greater the air flow, the more power it is capable of. (The engine is just an air pump, the more air, the more power) Check out this link for a comparison of different heads. There are different categories at the bottom based on intake runner size. http://www.chevyhiperformance.com/te...ench_database/

As far as the camshaft goes, you want to get a camshaft with enough lift to maximize air flow for that particular head. Some heads only flow good up to .450 lift. If that is the case, you won't need a camshaft with a greater lift. Each cam also has 2 durations...the advertised duration and the duration at .050. The advertised duration is the duration that the cam manufacturer uses when it measures. However, each manufacturer measures it differently, so they also use a universal duration, which is measured at .050. The longer the duration, the worse the idle, but you have the potential to make more top end power because the valve is staying open longer. Usually the lower duration numbers produce more torque. A good street performance cam might have a 218-228 duration at .050.

Also, if you are looking for tried and true combinations without the guesswork, check out this page. There are over 100 different combos.
http://www.ryanscarpage.50megs.com/combos1.html

 

Thank you dgruenke but this is exactly why I am getting more confused by the minute

If there were only 1 or 2 combos then Im sure I could make a choice
Thanks for the info

 

Bob:
Many companies make ubiquitous Z28 springs ... most shops know what they are ... but here're 2 examples: Elgin P/N RV943X or Sealed Power P/N VS739R. Fresh Z28 springs a step up from FRESH L48 springs.

Fresh L48 springs are relatively weak ... your old ones are considerably weaker. Plus, a new & stronger cam will like a spring upgrade from stock.

Your old pushrods & rocker arms may look fine ... but they're worn ... and they've been through many cycles. Stronger springs will put additional stress on them ... that's why I suggest new, inexpensive replacements.

Don't worry, a 2bolt block will reliably hold this combo & LOTS more.

By "have em straightened & serviced" ... I mean have them milled (surfaced) enough to straighten/level them ... probably 0.005"-0.010" ... that'll also give a slight CR increase. Service can include whatever it needs: reseat valves, install thin-wall bronze guideliners, install real valve stem seals atop guides, install & properly shim-space new Z28 springs.

I suggested a new hydraulic flat tappet (lifter) cam. Anytime you install a NEW flat tappet cam you MUST install NEW lifters ... or else both will almost certainly fail.

The vortec head swap is a viable option ... they're great ... but that option blows the crap out of the $500 limit I suggested. I've bought good used ones locally for $150-$200/pair ... others may pay more. You can get clone of performer intake specific for vortec. Professional Products P/N 52007 about $123 @ Star 1-800-625-9454. Star also has those elgin springs for a buck each (16) ... get a catalog ... inexpensive source for many parts I reference & more. And if you don't have one already, Suggest a "How to rebuild Small block chevy" book at local bookstore about $15-$20 ... loads of practical info.

 

Thanks again Jack
Im going to go and talk to a couple local machine shops tomorrow and bring the info that has been posted in this thread

 

Bob, there is no need to get all stressed out about this. It's real simple, if you want to get more power from your engine it needs to pass gas. You can help it do that with headers, a better camshaft and some head work. You already have the link for the headers and, if you want to save a little money, here is another camshaft you may want to look at (#270-967601).

http://www.jegs.com/webapp/wcs/store...tegoryId=10707

If you don't want to have the car tied up for more than a few days, you can get these and take them to a head shop to have them ported.

http://cgi.ebay.com/ebaymotors/Fresh...57906540QQrdZ1

That way, when all the prefabbing is done you just swap parts out. You can have it done in a weekend.

BigBlockk

Later.....

 

Thanks BigBlockk
I will order the camshaft, the only question is about the heads
Are these the same heads I have on the engine now? (194/150)
I know for a fact that they have no more than 7,000 miles on them so I would rather have my stock heads rebuilt (if necessary) BUT I am not opposed to buying another set of heads (smaller chamber to increase CR) if it will increase the HP....Which I think I would rather do As long as they come complete and ready to bolt on


I dont want it to sound like I have money to burn but at this point, I really dont care how much this job will cost, as long as my Corvette isn't tied up for more than a few days.
I guess by now you have figured out that I am not long on patients

Thakna for all the help

 

as long as your within an hour driving distance, I can swing down one weekend and pull the radiator out for you..

I'm kind of a pro at this by now

 

Hey Corz
I could use the help with the entire job
From your town to where I am is just about an hour (used to make the trek every other weekend to drop off stuff for a wacko friend who was "A guest" at CVH

Im @ Exit 9 off 84 west

I would gladly pay you a very fair Wage if you were to help me get the entire top end job done.
Is this something you are capible of doing?

Thanks
Bob

 

Those heads are the same ones you have now. I didn't think you wanted to tie up a bunch of money in this project. If you don't mind spending some cash you could always get these. Look at #033-911J.

http://www.jegs.com/webapp/wcs/store...tegoryId=10187

They are the best street head you can get and they will not need any porting work at all. I believe you can order this same head with 64cc chambers. Just bolt them on and go.

BigBlockk

Later.....

 

Thanks BigBlock
I cant thank you enough for all the research you have put in this project......and that goes for everybody that has responded.

I dont see the 64 cc's but Ill keep looking

 

Bob O:
Those are all good suggestions ... but ...
I don't understand why so much $ ? You indicated you're seeking only about 60 more HP at crank from a stock L48 ... a motor that's notoriously undercammed ... meaning just a smidge more CR & a mild cam will easily get you there. My .02 ... Big money on heads is a waste for this application (overkill) ... porting nice but not needed nor are "name" brand heads ... you want only about 60 more HP from an L48. And the right cam profile is the right profile ... whether you spend $70 on a C&L kit ... or 2-3 times that for a "name" brand ... again, you only want about 60 more HP from an L48.

If you feel compelled to add heads ... why not first check w/ a coupla local machine shops & see if they'll lowball a pair of vortecs or 64cc doublehumps that someone failed to pickup/pay bill? ... It does happen. G'Luck

 

I've never done a cam swap before, nor have I had much experience with adjusting rockers either.. but I can take s**t apart like nobodys business

oh and you dont have to pay me.. I'll gladly help out for a forum buddy

 

Hey Jack
I am leaning so far from one side of the fence to the other Im going to wind up with Hemi's (Roids, not the Mopar engine)
Im now thinking I want a little more than the 60 FWHP I had originally stated
I firgued that if Im going to tear the top end apart, I might as well go for all I can get (within reason)
Your advice is very much appreciated
By the way, I sent you a PM... I hope you got it
Bob