Cam you dig it?

[CopperNick]

78Delta88, me back again. The block number on my engine is 14010203, which makes it a 305 CID according to my casting numbers reference book. It was foundered/manufactured for use between 1980 and 1985, and the application was for Pass, Malibu, MonteCarlo, Camaro, Truck. Since I pulled it from an 1985 C-10 Chev p/u, it was correct for that vehicle to begin with and, as llsted, subsequently correct for my Monte.

The reference text also notes that there were two other castings, both 305, c/n 14010201, and 14010202, Both were manufactured for use in the 80-85 Pass, Malibu, MonteCarlo, Camaro, and Truck series of vehicles. Not sure why three separately numbered variations of the same CID. I did score the third version, 0203, possibly this was the block that was destined for the "HO" designation. My reference text does not go into that great a depth of detail. From all sources and comments, that "HO" was more of a publicity gimmick than something tangible and real.

As for the notion of adding/using Vortec heads, now I will have to unbury that long block 305 and see what the head numbers are on it. The rocker covers are centre bolt which is supposedly one sign of what might be underneath. Once I snatched that motor out of the engine bay, it just went on the dolly in all its filthy, grimy glory and there it has sat I had no idea as to what it's pedigree was, only that it was not politically correct for what I had in mind for this build.

Mind you, 85 Monte's didn't come with factory four speeds either, so at least some of that PC quest has gone by the board but, hey it sure knocks some of the snot out of the looky-lou's.

It is beginning to sound like, unless the bosses in the cam valley for the retainer frog miraculously got casted into pre 86-87 305 blocks, then finding a roller cam with an acceptable RV grind machined into it is about to be added to the unobtanium list.


Bother



Nick

 

[78Delta88]

The 200 series had thicker and solid webs for the center caps. Properly done you can go splayed billet caps, but as a home DIY'er you can use the 2 to 4 conversion caps which are drilled straight. Works very good with ARP 12 point stud 4-bolt main kit.

Machine shop just needs to align bore. Which should drill and tap the extra holes as well. The shop I used only charged me 150 to dip, bore and align bore, so I did the caps myself. Probably maybe not for everybody to drill the caps. I supplied him with transmission and differentials from scrap cars so he did most my work for little over cost. He closed down 2017 so retail will be a little more, not sure your area.

Check the heads ... 416 or 601 is HO. Not common but largest intake will be 1.94, the regular 305 will be 1.72 intake. All exhaust will be 1.5.

If you do any head work, focus more on 1.6 exhaust and good porting and unshroud the intake.

 

[78Delta88]

Some decent comments on 305 Heads.

Also note, this race builder also mentions 220 duration.

 

[78Delta88]

Hope I didn't overwhelm...

Basically the HO had stronger bottom structure to reduce crank walking and the heads had bigger intakes and a little better flow.

If using the stud kit, works well with the Girdle and or windage tray. If turning RPM for longer duration or romping on it heavy use the M55HV with the 3/4" pickup. And what's nice is any 350 forged rotation part will work. Forged pistons are available but can get very expensive.

 

[CopperNick]

First, would not need to go aftermarket for the 4 bolt main caps; I have a set sitting on the shelf that I salvaged from a 350 block that had been tossed, Think the problem was spun bearings or along that line and the owner had elected to score another engine rather than spend the money on a rebuild or reman. They are straight up and down, not splayed. ARP would be the vendor of choice for a 4 bolt stud kit, or I might go with studs in the oem holes and bolts for the outer ranks. Going with the studs in the oem positions offers better clamping for the cap and the bolts in the outer rows would be security against cap walk. They also make it easier to lift the caps in the event, sometime down the road, that the crank has to be revisited for whatever reason. Big problem for me is that I still need to find a local machine shop that has the knowledge and expertise to do that kind of work. Nowadays, you bring a block or heads in for modifications and you get confronted by the "Well why don't you buy.........................." instead of any enthusiasm for doing what is being asked for.


As for the heads, going to agree with your author about breathing and horsepower. The best valve combination for the gen 1 heads almost always was the 2.02 intake/1.60 exhaust, and I doubt those could be swapped into the 461 head without a lot of work. Thinking both the valve pockets in the heads and the cylinder bores at the head gasket face would have to be relieved or crescent flycuts made to provide room for the valves. The cylinder work would be necessary or the valve heads would crash into the cylinder sleeves. In Doing that kind of modification there is always the chance you can breach into a water jacket and your block is junk, or off for a very expensive repair.

When the author of that think piece mentions the cost invested in the research and machine work he had done, I tend to suspect a lot of it involved extensive port matching and reshaping of the intake and exhaust runners for better flow. Since he had the limitation of the valve sizes imposed on him by the basic architecture of the head, the only thing he could do was to try to optimize as much as possilbe the movement of the air/fuel mixture from carb to piston. If you happen to have access to a lot of donor heads to experiment with, then Hey, all you need is time, money, expertise, and the right tools to work with. For the rest of us, as noted, it is probably better to find an aftermarket head that will meet our needs at a decent price and skip the lab time.


Nick

 

[Clone TIE Pilot]

The best factory 305 heads would be the "059" Vortec heads used on L30 engines. They are not quite true Vortec heads as they lack the Vortec style chamber but do have Vortec style runners which requires a Vortec intake manifold. Supposedly they are the secod highest flowing factory SBC heads just behind 350 Vortec heads.

 

[78Delta88]

As far as what I was told, yes, the 305 Vortec were the best OEM iron for the 305.

On the valves I would focus on 1.6 exhaust, before worrying about intakes. If 1.72, maybe pay to go 1.94. 2.02 or bigger will contact the cylinder wall unless you machine in the reliefs needed.

I never went that far. In Tucson we had a guy that did the machine work at home, had the equipment there. I think he may have passed, he was in his 70's and did the work basically for something to do.

On the 305 race blocks and RaceSaver 3.801 bore was the maximum to clear tech. And the RaceSaver used the Brodix, serial numbered heads that were flow restricted. I left those alone. I would build the 4 bolt main short block but when you get into Brodix and the injection system, I wasn't a fan of having a 10 grand build and hoping to sell to make it back with a little profit.

Yet then again, a lot of money to spend when in reality putting it into a 350 or 383 build made more sense.

 

[64nailhead]

Someone mentioned that you can use roller lifters on a flat tapper cam. Ummm, you can for a minute, but that’s about it. The roller cam lobes are flat whereas the FT cam lobes are not so as to facilitate the lifter spinning in the lifter bore. In other words, DO NOT put roller lifters on a FT cam.

Regarding the 256 Isky you have, I’d chuck that in there with a quality set of North American made EPDM lifters and call it a day. Just be sure the lifters rotate in the bores when the engine is spun over by hand.

I know you and everyone else has hammered the 305 to death. But for a cruiser it’s fine. No need to try to hop it up. That ‘hop it up’ money is best spent on that 400 block you have in the shop.

 

[78Delta88]

If you do go with the 400, i know where a forged 327 crank is. It is 3.25 stroke. Makes a 352 there or about with +30 over bore.

Using a 350 crank gets you about 377 which was old school NASCAR build, but not used any more. 30 over bore gets you 4.155 which is a lot of meat, but wind that up to 7000, would be fun street car.

 

[64nailhead]

I agree. A short stroke larger cube motor makes for great fun.