Right now I have a LG4 with a Performer RPM intake and Performer 600cfm carb, summit headers, stock heads and stock cam.

I am either looking into beefing up the 305 or buying a 350 that has 283 power pack heads.

With the 305, I was going to get new S/R 305 Torquers heads and Comp Cams XE262H-10 "Xtreme Energy" hydraulic flat tappet cam. (I saw an article on the web about making the 305 have 300-325hp) I think with that setup with what I already have, I should get to 275 to 300 hp from the 305.

With the 350, it is bored over .030 and it has 283 power pack heads (I belive the heads were worked to have a better flow) with this setup it would make a lot more torque due to the higher compression, but loose top end hp due to the lower flow (well from at least that is what I was told).

I was trying to figure out what would be the best setup for this 350 engine. I was thinking about not using the RPM intake due to it seemed to be better for high end hp (1500 to 6000rpm range) but I was not sure what intake would be good to use with the setup that I am looking at. I also was wondering if anyone had any ideas on what cam would work too.

I myself am not a motorhead, but I know most of the obvious stuff so any help would be appreciated. Thanks!

 

Not a good plan...

Besides those heads being almost 50 years old and about 45 years out of date now, they lack the accessory bolt holes that have been required for the last 35-40 years for installing the accessories on the front of the motor.

If I had a set of those, I'd sell them off; and turn the cash into something good for the 350, like Vortecs maybe.

About the worst thing you could do, IMO, would be to spend money on a dished-piston 305 when you have a 350 sitting there that you can get nearly 1½ times as much power out of for less money.

 

The performer RPM intake, carb and headers can be moved from 305 over to 350. You'd only need some decent heads (or port the 305 ones to keep costs down), throw in that compxe262h and you're ready to rock. (on the 350 i'm talking about here.)

 

"there's no replacement for displacement,"

Old school thinking that never loses style. There really is NO reason to use a 305 if you have access to a 350.

283 power pack heads are out of style, not to mention functionality. Those S/R 305 heads are better nowadays...

Not bashing your stuff, I'm just saying that you have much better options now.

Good luck!

 

Seems everyone so far thinks the 350 is the best way to go, I thought the same thing too but I wanted to see what other people thought with their knowledge and experience.

So if I buy the 350, I was thinking of buying the Edelbrock RPM Heads, and the matching RPM cam to go with the RPM intake that I already have. Or would buying the World S/R Torquers Heads and Comp Extreme Energy Cam be a better way to go. And what would be the difference between the two setups.

Also can some one explain the difference between 67cc or 76cc chamber on the World heads. Or the difference between the RPM Heads and the World heads. (Like I said I am not a motorhead, but anything I can learn will be helpful)

Thanks!!

 

The RPM heads are an excellent street part. They WILL NOT make the highest dyno numbers, and they WILL NOT go the fastest at the track; but they are VERY well-designed for street duty, where the engine has to operate over a very broad range of conditions, and some of those other conditions are more important than just simple max power. Their heads, within their specific application, are very good, and their intakes are very good as well.

Don't buy the RPM cam. It's terrible. It's not "matched" to anything. It's been around since long before Vic Edelbrock was making heads; like, 20 years or more before. It's just what they could get cheap. For that matter, you can get the same thig for about 1/3 the price yourself, as the Summit 1107. http://store.summitracing.com/partde...art=SUM%2D1107 Look familiar? It's a copy of a copied copy of a design that's been around almost as long as the power-pack heads. Entire generations have been born and grown old and started to die off since that thing was introduced, back when 327s were the hot new "big" motor.

it's very easy to get a newer cam that will produce the same power, or more, compared to that old thing; with less of the familiar "big cam" problems of low vacuum, terrible gas mileage, difficult tuning, poor low-end response (gutless leave), poor cold weather manners, etc. etc. etc. Or, to turn it around the other way, at any given level of those "problems" that you're willing to deal with, any other kind of cam will make more power. The Comp Xtreme series is pretty much state-of-the-art as far as design; the Lunati Voodoo series, and various offerings from Crane, Crower & Isky, are in that same league. That's where you need to be looking. In fact, the Comp XE274, or the Voodoo that's slightly smaller than that (the 60103 I think it is), are 2 of the best actual "matches" to the RPM heads. Much better than that relic from the Stone Age.

Likewise, DON'T buy anything specifically for a 305, like the 305 S/R Torquers. That's just not a wise use of money. When you get disgusted with the 305, as you surely will, you'll have this pile of stuff you have to set off in the corner of the garage and buy something else equally costly to replace it. Bad move.

Chamber size is just that; the volume of the chamber. The bigger it is, as a proportion of CID, the lower the compression. With a flat-top 350 that has had the block shaved down to where the pistons come up exactly even with the deck ("zero-decked", we call that), a .039" head gasket such as a typical FelPro, and 64cc heads, the CR comes out right close to 10¼:1. Just about right. 76cc heads are better for full-size motors, at least 400 CID (or boosted small ones), and should be avoided for little ones like 350s. One of the worst mistakes that can be made, is to use large-chamber heads, and dome pistons. That combo has been proven time and again to produce poor results on the street. Might be OK for a pure race-only motor; but NOT for the street. Flat-tops and medium chambers, or very small chambers with "reverse domes" (a small dish on the piston top that's a mirror-image of the head chamber), are the way to go.

 

Agreed, that's a great writeup sofa.
The best chamber setups are small chamber with a dish piston. You want the chamber to look like a sphere, with the spark plug tip directly in the center.
This way the flame expands equally in all directions before exerting any downward force on the piston (ie. negative torque or pumping losses). That's because the piston is still rising at the time the flame front hits it, so you want the flame to hit the piston as late as possible.

With a dome type piston, the flame front hits the piston much sooner, producing lots negative torque while the piston is still rising. This is why large chamber-dome piston setups don't fare well on the street. In all out power-high rpm engines this doesn't manifest itself as much because at high rpms the engine outruns the relatively slow moving flame front. At low rpms however, is where you see most of the problems from this.

And don't forget to get your nice tight .035-.040" quench distance to produce the most turbulence within the chamber.

 

Thanks for the advice it is very helpful!

I will look into what kind of pistons are in the 350. I know that it was bored over .030 and I see what cam is in the motor now.

I was wondering if someone can explain the difference (maybe it is just as obvious as it sounds) with the RPM intake vs the Performer intake with the power band with the RPM from 1,500 to 6,000 and the Perf from Idle to 5,500? With the RPM what does it mean then from Idle to 1,500? Sorry if this sounds like a dumb question, I just want to make sure that I understand.

The other question I have is I was thinking about saving some money by buying the World S/R Torquer heads, would that be a bad choice? Here is a link to the specs of the heads: (they say that it would add 30 hp)

http://store.summitracing.com/partde...0&autoview=sku

How would these rate vs the RPM heads:

http://store.summitracing.com/partde...0&autoview=sku

Are the RPMs worth the $200 more? I know they are Aluminum but will they perform ALOT better?

Thanks!

 

That's just marketing, re: performer vs performer RPM. You don't really lose anything from idle->1500RPM, I sure didn't notice anything (in that gigantic 700RPM spread there...)
The performer is a nice shiny intake of a *very similar design* to your stock intake. The RPM is a high rise dual plane, which actually increases power output. It's a no brainer.

 

Thanks Sonix, I understand what you mean. So it was just as simple as you explained. I will for sure just use the RPM intake.

I just need to figure out if the RPM Heads are $200 better than the World heads. Any one have any exerience with the World heads on a 350?

 

I would pass over both and go for the Etec 170 heads. They will bolt on and run on your 305 and transfer over to the 350 and run even better. They do take a vortec specific intake though.

 

Agreed, I'm planning on putting a set of these heads on my 96 1500 to replace the stockers when I do the rebuild. I've been looking at these for awhile now.