im getting to the point where i think i might wanna do my heads before i drop in this motor, heres what i have on it.

350 bored .030 over
forged piston heads & rods
rebuilt stock 79 blazer heads
edelbrock performer RPM intake manifold
edelbrock cam and lifters
edelbrock headers and y-pipe
3in catback
edelbrock 650 cfm carb
accel distributer
8.8mm wires
platinum plugs
cloyes timing chain set-up

... what heads do you think i should go with? id like something better than stock but not too expensive, also would it be worth it to bring them to a machine shop to have them port them out? someone was telling me about 202 or 205 heads what are these?

 

202= heads with 2.02" intake valves 205= heads with 2.05" intake valves.
How much do you want to spend on heads? Remember, the heads are one of the biggest factors that can limit power production.

 

79 blazer heads, if off a 350 sound a lot like 882's or similar trash. If nothing else look into some world s/r, or something similar. Not the best but not the worst. Another good choice would be some ported 305 heads. Word of advice though, if you are going to pay to have them ported, just get some aftermarkets. By the time you pay to have them ported, and machine work for bigger valves, you could have just bought some aftermarkets.

 

would my 305 heads work better on the 350?

 

Yes if you port them and unshroud the valves. Even if you just unshroud the valves to increase the chamber volume, they will be way better than 882's.

Also dump that cam, it is junk, a really old design and will really hold power back. You could have gotten the exact same cam from summit for 1/2 the price. But its still not worth running.

 

what cam should i use then?

 

I see that you have an RS. Does this mean that you have TBI? If that is the case then your 305 heads will NOT be a good head. They are worse than the junk 882 pos crap that came with that blazer. Well, maybe not, at least they may have compression in thier favor. The point is, they are swirl ports, junk. You want heads from a 305 TPI or LG4 or L69. 416 and 601 are both numbers that come to mind. Do a search and you will see. Just stay away from the swirl port wonders.

 

yep just stock tbi junkers, but i dont think i have the cash to get diff heads now unless theres something good i could use that came from GM and i could find in a junk yard for cheap, but as far as the cam goes, what should i use with the crappy swirl ports? i no nothing about cams right now, so any help would be cool, i just want something better than the edelbrock cam that i could use with these heads and get a little more from them, even tho these are the biggest downfall on my engine, thanks alot guys

 

No cam will make any difference, with those heads. The heads gotta go first.

Look for 081 castings, which is the ones that came on 87-up LG4, L69, and LB9 305s.

Don't make excuses for replacing something else. The excuses won't make the car go any faster. Spending money on something else while those heads are still there will simply delay the day your car will go faster. Save up your money, and get the right heads, and go from there.

 

Not that I would ever disagree with RB, but if the Edelbrock RPM intake you have is set up to bolt to the '79 vintage heads, you might want to look for '416 head castings instead of the '081s. The '416s are essentially the same inner cores as the '081s, but have the center set of intake bolt holes drilled and tapped at 90° angles to the intake flange, instead of the 72° angle of the later heads and intakes. If the RPM is set up for either bolt, choose either head casting. Both castings are set up with all necessary accessory bolt holes, exhaust crossover/EGR ports, etcetera.

You should be able to find a lot of resonable advice on porting either of the two suggested head castings for really decent flow, and a little advice on enlarging the valves and unshrouding the chambers so they work well over your 4" bore.

 

You don;t say which "edelbrock cam" you have.

Is it the Performer cam or the Performer RPM cam?

Go to the junk yard and look for a 305 motor with a carb.

Remove a valve cover and read the casting number off the cylinder head. You're ;looking for 416 being the last 3 digits. BUy the heads, or the whole motor, or the whole car. which ever is $$$cheapest$$$

Home port and rebuild the 416 casting heads with 1.94-1.60 valves and a new valve job. Do not pay some one else to port your own heads DO IT YOURSELF!!! You can F*&^ it up just a good as a "pro" can.

Big improvement over the heads you have now for minimum $$$.
If you are just not up to porting your own heads, buy some entry level assembled 64cc high perf heads like Edelbrock Performer RPM heads or Trick Flow 23deg G2 or Dart 180's GM Vortecs are nice too.

The performer RPM cam is a little big for your purpose.
I'd switch to a milder grind. about 216-222 @.050"
yes you will need new lifters.

 

Why buy 305 heads? 350 heads from a JY will be the same price and be a proper match to his engine.

 

Yes and no. THe 305 head will have the advantage of higher compression in the end, albeit not a lot, but a little. Might as well take advantage of it. Also, a set of ported 416s will outflow the L98 heads, IIRC.

 

http://cgi.ebay.com/ebaymotors/ws/eB...ayphotohosting

how do they look? they arent too expensive, and are right around my budget for now

 

1.84 intake valve size isnt that even smaller than the 882 castings?

 

Valve size doesn't really matter that much. The 416's have a large 165cc runner, which is about the biggest GEN I head made. The runner flow really well, and the small combustion chambers allow for unshrouding the valves without killing compression.

If the heads need a valve job though, you might want to have the seats cut for 1.95-1.6" valves.

 

http://cgi.ebay.com/ebaymotors/ws/eB...category=33617

Ive seen these sell for 500 and ya wont be wasting money on machine work

 

Well, they will, but at a cost. Reduced quench area or too large depending on which head gasket you use, a nice little "crevas" made by the smaller bore head on a larger bore engine that can help induce detonation, possibly too high of a compression ratio.

They won't out flow a properly ported set of 350 heads, not to mention no added expense of having larger valves/seats installed and a properly fitting head gasket

 

Depends upon what 350 heads your talking about. Vortecs no, Camel/double humps about equal, 461X, probably not.

416's have 165cc runners stock, the only one that i know of that was bigger was the 461X heads at 170 or so. But got luck finding them.

 

may be a very broad question, but wat kinda car/truck would have these haeds i need?

 

82-86/87 RWD vehicles with a 305, you can find 416's on pretty much everything that doesn't have TBI.

 

Funny how many people here run those exact same heads and never have any of the promblems you have described. That includes myself. 350 heads is a broad blanket of description. That could be 882, 993, or whatever garbage the yard has in stock that day. They will outflow most 350 heads, and be a better bargain than the rest too.

 

Don't forget that with any used head the first thing you have to do is strip em, clean em, and Mag em for cracks!! Most yards will agree to an exchange if their head comes up cracked, they're just interested in the weight... I am amazed by how many guys will trust a buddy with a "good running" set of heads, and then they fail Mag due to 1/2" cracks developing in the valve seats!

 

Whatever, its not my engine.

 

That is not much of an acknowledgement that you are incorrect!

A lot of people are surprised to find out what great little castings the 305 heads are

 

You're right, and I'm not acknowledging it..and I'm not going to argue it with you either.

 

bottom line, what should i go with lol?

 

Wanna save some cash, and get some decent heads? Pick up a set of 305 TPI they are 081 IIRC. Or some 416s. The 416s were found on all of the LG4 engines and L69 engines too. Port them yourself, contrary to what people argue here, it is not hard to do. Rather easy. Have them cut for bigger valves and you are done. Follow the spring specs of your cam manufacturer.

 

thanx ljnowell you always point me in the right direction lol, also, would L98 heads work? i got a pair on a friends car, he only wants 25 for both, if not ill look for 081's thanx

 

As warned above, make sure they are exactly what they are supposed to be (083 castings), and are not cracked.

With the port work, they will work great. Basically the only difference between the 083's and 416/081's is the intake valve and chamber sizes. By the time you get 416/081's ported and the larger intake valves installed, with the proper valve deshrouding, you have basically the same head as ported 083's. The port sizes are the same.

As ljnowell said, porting them isn't that hard. I know, because I've done it on two sets of heads; and if I can do it, most anybody can.

 

Thats kinda how I feel too. Yeah, the L98 heads have 64CC chambers, and when you are done with the 305's they will have around 62-63. Not a whole lot of a difference.

 

what tools will i need to port these heads? i just got one of them new dremel xpr's, is that enough? or will i need air tools of some sort? also what kind of bits? i am new to this and any help would be greatly appreciated... also do you guys know any links to pages with pics, or maybe a "how to". im not trting to be spoon feed, but this would just make it easier... THANX A MILLION

 

http://www.sa-motorsports.com/diyport.shtm

I printed them out in early 2001 and read them over and over again. The same instructions are included in their Deluxe Porting Kit in poster form - when I started the job, I hung them over the bench so I could read them as I went along.

A couple of carbide burrs are good to add to the kit - a "tree" burr and a small and medium ball burr are helpful. Some people just use the burrs and don't bother with the stones & rolls.

Some people use the pneumatic die grinder as they show. That requires a good air compressor, much more than the typical "6 HP (Peak) " compressor people have in their shop. Others go for an electric type with variable speed control.

Best advice I've heard since I did mine is to set up a shop vac on the opposite end of the port you're working on to collect the dust as you go. Otherwise, it gets everywhere (ask me how I know).