Hey all. I'm sure all of the information I am about to ask is already on here somewhere..but my eyes hurt from reading so much. So I am just going to ask...


I have decided to do a 305 to 350 swap in my '92. The 350 motor I have is somewhere in the late 70's but I'm not positive on the year. My biggest question is, what do I need to do to this block to make it hold my factory serpentine belt setup? Is this even going to be possible? I will be using my camshaft, heads, rockers, and headers from my 305, as well as converting it to a TPI intake system. Basically, the only thinkg I will be using from this early 350 is the block itself, and the lower rotating assembly.

Any input is greatly appreciated! Along with any food for thought on something I may not have considered.

Thanks in advance for all your help!

 

Bolt it on.

Your cam won't work*. It's a factory-designed roller lifter with a retainer plate. Older blocks used flat tappet lifters and no cam retention.

Unless you have something other than TBI heads, you won't want to use them on the 350.

You will also need to get a different flywheel, since your '92 engine is 1-piece rear main seal, and the older crank will be 2-piece rear main seal. Just get one for the '83-'85 f-body V8 manual transmission application.

*You can use a factory roller cam in a non-roller block if you get retrofit roller rockers and get a cam button to hold the cam back in the block. It would be cheaper, and you'd have a better product in the end, if you just bought a flat tappet cam/lifter/timing set kit.

 

I have the stock TBI heads, but I failed to mention that they have already been ported, polished and decked. They have also had a competiton valve job and larger valves installed (1.94/1.50) There are also heavier springs installed (not sure on the pressure rating. Machine shop installed them when they built the heads for me)

 

Also, thanks alot for the info on the flywheel. I did not think of that.

As far as the cam goes, I did find on here while doing research that I will need to get the retro-fit lifters to use my cam. The cam that I will be using (currently in the 305) is an LT-1 cam from a '94 SS. The cam button is also something I did not think of. Will I need to use an aftermarket timing cover to accomidate that? And what about timing set...stock or double roller?

 

Sorry to hear that. A lot of money spent to get less than different heads would do without any work.
You don't have to use an aftermarket cover to use a cam button. A stock-type timing chain is fine.

The retrofit lifters alone will cost more than a flat-tappet cam/lifter/timing set kit.

 

Don't necessarily agree on the head part. Granted, there are much better ways I could have spent my money. However, it would take me a day to explain what this guy can do to a set of heads. (He made 438 c.i. out of an old 350 block, installed it in a 94 S-10 balzer, and runs 9's on pump gas. That's pretty good if you ask me.. But yes, some nice aluminum heads in the future would be nice

As far as cam, I think I see what you are saying. Even though I'm planning on installing a TPI system (harness, computer, the works) I would still be better off just going with a flat-tappet cam, lifter, timing setup? How about my Proform roller rockers? Are they now useless?



Wanted to also mention, I am in no way arguing with you on the head issue. You guys are the experts, and that's why I came to you! I was just throwing my in on it.

 

I'm guessing that 438 didn't have TBI heads on it.

I don't care what magic he can perform, TBI heads don't improve with porting and larger valves. The only good thing you can say about them is the exhaust ports flow well. You can't make the intake ports flow well enough to take advantage of that.

Your roller rockers should be fine. Most likely they are self-aligning, if you used them on the 305. If that's the case, just don't use them with guide plates or heads that guide the rocker with the pushrod hole.

Yes, an inexpensive flat tappet cam & lifter kit would provide more performance for less money (assuming you want the best performance for the money spent).

 

You're correct, the 438 was a carb'd motor with aluminum heads.

I also see your point with the TBI heads.

Yes, I did use the roller rockers on the 305 and yes they are self-aligning.

I will certainly look into going back to the flat-tappet if that is what is in my best interest. I really appreciate all your insight and help!