Greetings, I have read other threads about 305-350 carb swaps. I am looking for suggestions for a very budget 350 engine that is still strong. I will shop for used parts and need to know which available parts will work well together. I want to use the factory accessories. I intend to use aftermarket headers, intake and carb. If the vacuum advance distributor that is present is working properly, I will use that too.

At present, I have a carbed 305/5 speed. It has all accessories. It must be an older 70's 305 as it has the dipstick on the driver's side. I know nothing about the engine and if I am putting money into an engine, I would rather put it into a larger displacement engine. This will be a occasional use vehicle w/street engine so low/mid-range torque are most important. I want the engine to fit under the stock TA hood.

There are several engines available locally:

350 TPI long block core 400
350 ZZ4 longblock used 800 10:1 compression claimed
350 4 bolt shortblock rebuilt 600 large domed pistons

The guy with the TPI longblock suggested vortec heads but said I would need a more expensive intake. I would like to keep this swap as simple as possible, and use the most available/cheapest components. Which stock heads with which bottom end for 9:1 to 9.5:1 compression.

Suggestions with cost estimates greatly appreciated.

 

If the one called 350 ZZ4 longblock really is a ZZ4 longblock, that's the one to get. Aluminum heads, standard intake pattern, no exhaust cross-over passages, roller lifter cam (and a pretty good cam at that). The 10:1 CR is equivalent to 9.5:1 CR with iron heads. Any idea what shape it is in?

The 2nd choice would be the L98 longblock. Vortec heads if you like, but stock L98 heads work very well with basic port clean-up, valve stem guides cut for postive-type stem seals, and aftermarket valve springs and retainers. Disadvantage would be the '87-up intake bolt pattern.

Avoid the shortblock with the domed pistons.

Assuming you go with the ZZ4, or with the L98 with cleaned-up heads and upgraded cam, a 650 double pumper carb and Performer RPM intake would make for a nice combo with your T5. Don't plan on beating on the T5 very long, though.

 

The ZZ4 short block has iron vortec heads. Any cheap way to lower the compression on this engine if it really is 10:1?

I do not think the TPI has aluminum heads. Assuming iron heads, what machine work should I do to the heads for using an LT-1 cam? Are screw in studs necessary? What would be a reasonable budget for the heads? IIRC, these engines are fairly low comrpession. Any advantage to raising the compression? Any inexpensive way to do this?

Keep the stock bottom end on the L98?

The 650 dp and Performer were my initial thoughts for carb/intake.

 

If the ZZ4 has Vortec heads, it's not a ZZ4 longblock - it may be a ZZ4 shortblock with Vortec heads. I'd find it easier to believe it is a '96-up truck engine, or perhaps a 330 HO crate. Check for roller lifters. If it is a ZZ4 shortblock with stock Vortec heads, that's a problem, because stock Vortec heads can't handle the lift of the ZZ4 cam. If the lift hasn't caused a problem and the heads are stock Vortec, it probably isn't a ZZ4 shortblock - or at least a ZZ4 cam.

TPI could be aluminum heads, if it came from a Vette. If that wasn't specified, it probably came out of a 3rd gen. You can probably get away with aftermarket springs on stock L98 heads, as the LT1 lift isn't that great. Screw-in studs may not be necessary, but are good insurance. An alternative is to pin the press-in studs. New valve springs (and retainers, IMO, to eliminate the stock exhaust rotators) should be assumed, regardless.

Stock L98 bottom end should be fine if it is in decent shape.

 

I am supposed to look at the "ZZ4" on Thursday. Any identification marks I need to check for on the block/heads?

The TPI is from a third gen, '88. The engine has high miles so at least bearings and rings will be necessary. May need overbore and pistons.

 

Assuming the intake manifold is off (or if not, look through the distributor hole), see if roller or flat tappet lifters. Roller will have the sheet metal "spider" dog-bone retainer. Get the casting #'s off of the heads (both of them, not just one) under the valve covers, and the block on the bell housing casting behind the head. There might be numbers on the block pad in front of the passenger side head, get those as well. If the pan is off, try to get a look at the crank and main bearing caps.

There isn't a lot to be gained from all of this, but I'd sure like to know what I'm getting and what shape it's in before plunking down the extra cash they're asking for it. If the heads are 882's or 193's or something similar, you know you're dealing with either a liar, a con artist, or an ignoramus.