I was in the process of rebuilding my 305 when I got an offer I couldnt refuse. So now I have a gen I 350 shortblock with new rods, pistons, crank, and bearings and Im gonna throw my 305 heads on it for higher compression...

I was wondering if anyone had done this before and if you had any recommendations for the build OTHER THAN buying new heads. I'm puttin Tuned port injection on it

I'm going for low end torque... as much as possible but without sacrificing its drivability... It will be my dd

Im interested in the best cam specs (remember theyre 305 heads) along with any other suggestions for the build

Thanks in advance =D

 

This is a common thing, for those with dished pistons in their 350s. If you have flat-tops, you're around 11:1, and that's not gonna fly. As for cam, does your 350 use a 2 piece rear main seal or 1-piece? It costs much more to go hydraulic roller in the earlier 2-piece blocks, so you're probably looking at a non-roller setup if this is the type of block you have. Since you'll need tuning anyway, you may as well choose a more serious cam. Considering the flow of unported 305 heads, choose a cam with 6 degrees more exhaust duration at .050" for a roller, maybe something like a 212/218-110 .488/.495" from COMP. For non-roller, maybe a 218/224-112 .462/.469"

 

Its a 1 piece and Im going with a hydraulic roller cam im just not sure which to get ill look into your specs thanks =D and by the way I was reading that it might depend on my heads cuz im using my spare 305 heads I rebuilt which are casting number 376450 from a 75-81 305 (not ported cuz im gonna drive the car not race it) and those specs you gave me wont effect the drivability too much will they?

Thanks Alot =D

 

Forget those heads, even smaller valves, they don't flow enough, and they'll require you to change your lower intake manifold. Just swap your '89 LB9 heads to the 350 when you pull the LB9 out to make room for the 350. Then stick the spare heads on the LB9 and sell that.

 

The LB9 is already out and gutted lol so there is room now =P


but then Ill have to put new valve springs, seals, and etc./rebuild the lb9 heads and that gets pricey =/

heres a pic of the LB9 heads but its pretty dark =(

 

and why will they require me to change the manifold?

 

If you can't afford to do it right the first time, you sure can't afford to do it a second time. And you need springs anyway. Whatever springs you have are only safe to .480" lift. Spend $26 and get a set of 98111 springs from www.competitionproducts.com Seals are $10. The center 4 bolts of the intake got changed from 90 degrees to 72 degrees for 1987, except corvette. A word to the wise: stop considering the non-LB9 heads. The thing would feel out of breath and dead by 3500 rpm, even with a Comp Magnum 270HR10

 

Well that whole intake manifold thing does put a damper on it so Ill just rip the stuff off of my rebuilt heads (already have new springs capable of .550 lift) and buy some new intake valves (lb9 exh valves are the same as my new ones) and seals and just resurface my lb9 heads and that takes care of that but its just alot of work I was hoping was already done =P wanna get it on the road already =D

Thanks for all your help atilla didnt know about the intake manifold issue =D

Any other suggestions for my build that would get me some more low end torque?

Thanks =D

 

Any more low end torque and you will be breaking your T5. But you could step up from a 350 to a 383 stroker, but then you're back to running out of air too soon. The LB9 heads won't be too bad on a 350 to 4500 rpm, I suggest assembling it as an LB9-headed 350 with a 212/218-110 488/495 cam, and getting a feel for that, you know, getting a new baseline. Since your springs are good to .550, they must not be the stock replacement or "Z28" springs IO assumed, and 1.6:1 rockers would be great when you can add them, assuming you have adequate retainer to seal clearance.
If you're going to buy new intake valves anyway, buy a set of 1.94" and have the heads cut for those. A standard 3-angle, of 30/45/60 degree cuts, then a 75-degree bowl-hog. This would be worth 20 horses. You can get new stainless 1-piece swirl polished and undercut valves from competitionproducts for the same price as most local machine shops will charge for stock style valves. Have them put a 30 degree back cut on all 16 valves. If you can, polish the exhaust ports.

 

Hey what do you think of a
zz4 cam 208/221 @ .474/.510 112 LSA
or a
comp cam 210/220 @ .500/.510 114 LSA
found some for cheap just gettin opinions

 

The ZZ4 will work pretty well for you, it's just not ideal. I know you would like it better than the other cam you listed.