First, I want to tell you that I know very well your opinion about building-up 305 and I agree with you... B U T I live in a different location where you can't get 350 short block on junkyard even 500 miles away !!!. It's very hard to find one for the reasonable price (let's say 600$ - I would go for it) OK.
So I have 3 possibilities:
1. wait xxx months to find one for good price
2. buy one on eby for let's say 150 $ and pay another 600$ for shipping, fu... taxes etc. to get them.
3. start building my own 305 block (which I got for good money) to get some more power
Now, which one you would choose if you where me ?.

I want rebuild my '86 305 and have few questions:
1. Would you change flat cam to roller (already bought roller lifters Crane #818-16) ?
2. I want to stay with old crank and put KB153 .030 racing pistons for 6'' CR which should have 9,3 CR on stock '86 64 CC heads. - what do you think ?
3. 1,6 and 1,94 valves, with full porting heads, roller retainer 1,6 for already modified exhaust 3'' Dynomax collectors and new OEM (Edelbrock) Performer Non EGR intake. I have already LT1 cam would you stay with that one or go with some more aggressive for this application. ? On the top of it (please do not laugh...) for the moment there will be TBI with bigger injectors (or get back into carb ?)
Thanks for your suggestion.

 

Normally I would yell at you for staying with the 305, but I can see what you mean by location, so I guess that will pass, for now

The lifters you bought are retro-fit solid roller lifters by comp cams. If you want to use them, you would need a solid roller camshaft. There's nothing wrong with that fact, in itself. It's the fact that a.) it will be hard to find one tame enough for a 305 as most solid rollers are quite aggressive. 2.) Solid rollers GENERALLY do not like to play with computer controlled components, at least, not without extensive tuning/modifications.

The LT1 cam is for a factory roller block. You have a flat tappet block. The best choice for you would to be to buy a flat tappet cam and lifter kit that would best suit your desired combo. I'm not sure how easy it is for you to get parts over there, but Comp Cams has several of cams designed for EFI and factory controls and whatnot. For best choices and whatnot, I would probably stay with carb. They can take a slightly more aggressive cam design without all the extensive tuning.

For the rotating assembly, I would stick with pistons designed for 5.7" connecting rods, which is what you have from the factory.

For the 305 heads, the plans look good. Do you plan to have them machined for more lift as well (having the guide bosses milled down)? How about screw in studs and guide plates (not needed, but really handy).

 

Is there any particular reason for the new pistons? An '86 305 should have flat top pistons with 4 valve reliefs for 9.5:1 CR with '86 58cc 305 heads.

Any particular reason you're building the '86 instead of the '89?

If either or both of the shortblocks are in reasonable shape, you might as well save the money on the lower end rebuild and concentrate on the "bolt-ons".

If you go with the '86 block, stay with a flat tappet cam. If you go with the '89 block, go with the roller tappet cam.

My first inclination would be to stick with TBI if you drive this on the road regularly. If it's mainly for racing, the answer might be different.

 

Are you building your '86 or '89? One is carb, one is TBI.

 

Thanks for your valuable notes:
Stekman,
It means that even if I put retro-fit rollers lifters into '86 block I couldn't go with LT1 cam with proper cams limitation by camshaft buttons and retainers like this one: http://cgi.ebay.com/ebaymotors/ws/eB...tem=7924533226
If not, what is the difference between LT1 cam and any solid roller ?
regarding heads I didn't plan to machined them for more lifts and should I ?

five7kid,
Well yes, '86 block It's already disassembly and it seams that it needs to be bored over .030, so I couldn't use no more old pistons ?
The reason of rebuilding '86 instate of '89 is that I have no idea how much time and money this project will take ?. What If it failed ? I could still enjoy driving my '89 Camaro.Please remember that I can't just go and buy desired parts here. I have to look for them in US, which is time consuming job. Besides since I plan to build new engine I can sell old one which is still in good condition and gain some money
So you recommend stay with flat tappet cam instate of roller with older block ? Power/money ratio is not worth converting cams ?

ShiftyCapone,
I'm trying rebuild '86 which was previous TPI injected

BTW I intend to drive daily (just some weekend races)

 

The solid roller cam is designed like the flat tappet (at least any retro-fit). There are factory roller design cams that are solid roller, however, that still doesn't bypass the fact of ecm and tuning compatability.

Here's a glance at why they won't work (sorry about the picture quality, took them quick, forgot to turn on the close up).



That's a flat tappet cam on the left, a factory roller in the middle, and an aftermarket solid roller on the right. Notice the center areas on each. The factory roller is a smaller diameter (before the stepped area). That area on all 3 is where it fits into the cam sprocket. The factory rollers utilize a smaller mounting surface to accomodate for the cam retainer plate (a small plate that gets bolted to the block, the plate has a hole in it that the cam fits into. The center portion of the cam fits through, but the step cathes and prevents forward cam walk)

Another thing: because of the smaller sprocket mounting surface, the distance between the 3 cam sprocket bolts is smaller, meaning the factory roller cam bolts are closer together than a flat tappet. In the cam sprocket, there is a hole in the very center. This hole is where the cam button would go (the small plate then gets bolted around that, via the cam bolts, and holds the button in place. The hole on the factory roller sprocket is smaller in diameter than the flat tappet or retro fit cams. The cam button you show would not fit in the factory roller sprocket hole. The LT1 cam has the factory roller sprocket. Below is a picture of a cam button trying to be put into a factory roller sprocket:



Another thing is the crossing between the hydraulic roller cam and the solid roller lifters. Solid rollers are designed to have a lash setting. Since hydraulic tappets have the internal hydraulic mechanism, lash is taken up (zero lash) so no lash setting is required. The 2 CAN be crossed, however, you would have to run extremely tight lash settings, say around .1" or even less, maybe .080".

As for the heads, from the factory, at anywhere from .460" to .480" of valve lift, the bottom of the retainer will slam into the top of the guide boss. This is bad. Basically, taking them to the machine shop will increase the space between these to, and in turn, increase the amount of lift you can run, valve springs permitting. Which brings me to another point. The factory valve springs you have now are weak. From the factory they have about 85 lbs of seat pressure. They can only get weaker from there. I've seen used factory springs get rimac tested at about 50 lbs, one was just under. That is barely enough to prevent valve float at 5000 if that. And thats on a flat tappet. The roller tappet is heavier yet so spring pressures will tend to be a bit more. The 981 springs are a good aftermarket spring that could handle the LT1 cam.

My suggestion: sell the solid roller lifters and buy a Comp Cams K kit for a flat tappet camshaft. This includes the cam, lifters, timing set, valve springs, retainers, locks, valve seals (which you could sell as well, reasons described in a moment), and assembly lube. All this will run for about $350-$400 depending on which cam you get.

For the valve seals, all the positive seals from say, Comp, Crane, Manley, etc all require machining to the guide boss to make them fit. The only ones that don't that I am aware of are made by Fel-Pro and are made of Viton, not Teflon. Viton is about 1 step just below the level of "quality" as teflon.

Yes, if you bore the 86 block .030" over, you will need new pistons. Don't plan on getting too much for the 305 TBI.....that's one of the least desirable combos ever put in the third generation f-body (crappy heads, crappy cam, crappy compression).

 

Hi,
BIG THANKS for this explanation. Now I'm aware about the differences (photos are very helpful).
Now I see that the best idea is to go with flat tapped cam for this particular block.
Thanks again.
BTW1
Would you know whether mounting brackets of A/C, alternator, etc, will fit from '89 to '86 block. I'd like to stay with one belt system ?
BTW2
I just come back from the cinema (NASCAR 3D) - I WANT BUILD my engine !!!!:lala: :lala: :lala: :lala:

 

yes every thing should switch over from one to the other as far as accessories and exhaust and such

 

A buddy of mine in germany has 3 350 blocks sitting around, he could probably sell them to you reasonably.

PM me if you're interested.