HyperFlyer

92 z28 currently v6 wc t5. Yes z28 and v6 don't match 350 blew up v6 set up was $75. So looking to get rid of it now that I have to time and money. Application street strip. My options I have a 93 lt1 out of z28, needs rebuild and I would cam it. Then I have an option for a 1975 400sbc running for $700, would rebuild due to out of a junk yard. Either t56 or a v8 t5, but that's another topic. Looking to see what people have done and how it worked out thanks.

dmccain

iTrader: (2)

A 400sbc is a torque monster. I like them. Have one myself that needs building and I may put in my car later on. My dad built a 406sbc that ran 11s in a chevelle and had decent street manners. For street/strip I would build the 400 and save yourself the headache of the LT1.

five7kid

iTrader: (14)

I don't much care for factory 400's, unless you're willing to spend a lot of money. The heads are terrible, the pistons are cast & dished (and prone to cracking), the rods are short, the cranks are cast with large main bearings. The 4-bolt main versions are prone to crack the block. If you get a 2-bolt main block and are willing to spring for splayed caps (which means expensive machine work), get long rods and decent pistons, plus get good heads, you may have a good-running engine. But they can't take much of an overbore, and many, being as old as they are, have already been bored to their limit. A Hard Blok street fill highly recommended. You can do well if you build a 400 SBC from scratch with a Dart block, forged rotating assembly, and good aftermarket heads - you don't need a (overpriced) $700 junkyard engine to do that.

If the LT1 needs a rebuild, a 383 stroker kit is a good way to get a good-running engine. The heads are already good, although they can be made better with a CNC port job (along with the intake). The injection system is decent (better than any carb), and if you're scared about the Opti, it can be upgraded with the later vented version. '93 is a speed density version, tuning will be required.

Having said all that, I don't think much of a manual tranny for a street/strip application. Pick one or the other - street, or strip. An automatic is much more capable of handling both. If you stick with manual and strip, plan on a rear end upgrade (S60 highly recommended). 3-pedals are fun to drive, but they don't make a good multi-purpose vehicle.

HyperFlyer

If I built the lt1 it would be changed over to a 94-95 harness and pcm, avoiding the chip in the 93. Wouldn't do a 383 due to the cyclinders don't need it. Plus a decent rotating assembly can run some major $. A 400 rotating assembly isn't that bad. For the 400 its stock bore and would be given 6.0 rods and domed Pistons new crank. If I did the 400 it would be efi no carb.

five7kid

iTrader: (14)

'95>'94, as '95 has the direct vented Opti. It's not a direct change-over, as the drive changed. And I believe the connector to the Opti also changed.

I won't try to claim any "LT1Guru" status, as my direct experience is limited to a '96 Vette. Not sure how '94 or '95 "avoids the chip", as OBDII didn't debut until '96.

You weren't specific about what you meant by "needs rebuild". Not sure your parts source, but a 383 rotating assembly is no more than (and typically less than) a 400 rotating assembly.

All of the other issues still apply. I've looked into forged 400 rotating assemblies in the past, and they were pretty pricey.

Again, you didn't include that detail. FWIW, that's what I would do.

HyperFlyer

Very true should have given more information on condition and plans. As for the chip a 93 ecm for a lt1 is still like a tpi ecm using prom chips for tuning.

Back to the lt1 I would go through it and replace all gaskets and piston rings, hone cyclinder walls and mic the crank. Put 1.6 RR in and go with a comp. Efi cam. And the use a 94-96 harnes and a msd opti spark that's vented avoiding moisture build up. It's still driven off the front of the cam, the pin is longer for 94-97 lt1 cam. Decent Pistons getting about 11:1 compression.

400 sbc. Hopefully no cyclinder boring but who knows. Eagle rotating assembly about $600 rated for 500hp. 6" rods, domed Pistons for a aprox 10:1 ratio. After market aluminum heads 1.6 RR. Thumper cam. Mic the crank and so forth. Go either 4 barrel Throttle body or Holley stealth ram intake, money would decide that one.

If I missed something there sorry, really looking to see what people have done and how it turned out, not so much into the detail of how I'd build either or. And stick all the way Im no a fan of autos, still drive them but rather have stick.

sofakingdom

iTrader: (1)

In 2017, I would not swap a LT1 into a car. It's a good motor, makes great power and all that; but, it's "fragile" in the sense that there's ALOT of ways that it can break (few or none related tot he major moving parts like cranks etc.) including its ignition, and as old as it is and as few as were ever made, replacement and aftermarket support is weeeeek at best.

The 400 is the king of the small blocks. However a stock one, just yoinked out of some grandpa sled from 40 yrs ago, is ANYTHING BUT a "performance" piece. Don't hallucinate that a pullout is going to be "exciting" to drive. Think, tractor motor: enough torque to snap your neck from 0 - 5 mph, pathetic all the rest of the time.

I had one in my car, in front of a T-5, for about a decade and a half. Went through AHELLUVALOTTA T-5s. I'll never do that again.

A 400/T-56 though, might be a great combo. Make the block into a 434 with aftermarket splayed 4-bolt main caps; put some better rods in it, preferably longer than stock; use pistons with provisions for oil ring support, so the rod can be moved up as high as possible in the piston; then get heads THAT FLOW. No stock heads at all would be appropriate for this, 200cc aftermarket would be the ABSOLUTE BARE MINIMUM for it.

For my old 400 I'm seriously thinking about this...







I have the main caps as described above, a timing set w thrust bearing, some H-beam 6" rods, all manner of valve train goodies, the T-56, and various other such things for it too. All I need now (famous last words) is a crank and pistons plus a little machine work. And maybe a car to put it in...

HyperFlyer

Agreeing that a 400 sbc and t5 are poor combos, especially with my heavy foot. And dart blocks are pricy, idk how 700 for a complete running 400sbc is over priced. Most likely still going to build a mild lt1 instead of a 400, mabey down the road the 400 will replace it. But for now the lt1 is already in my garage with good heads, efi so good throttle response.

TTOP350

iTrader: (8)

Only thing I used from my 400 motor was the block.
My cam tunnel was the worst my machine shop had ever seen. (check that among other things)
Splayed mains, forged crank, eagle 6" rods and JE pistons.
Solid roller, afr 245s and a mini ram.
she runs fairly well ;-)

HyperFlyer

Any specs on the 400 builds, not looking for the insane money builds but not a crap motor. Thanks for all the inputs

sofakingdom

iTrader: (1)

The version that was in my car was stock-ish crank & rods, carefully ported 186 heads w Manley valves & 986 springs, small dish pistons (low 9s CR), Comp XR282HR cam, 1.6 roller rockers, Holley 6211 carb, DUI distributor, a few little tricks like lightweight piston pins and fuel pump rod, the old Z-28 pan w Moroso windage tray, T-56, 3.73 rear. Ran pretty hard, would take a LS1 car on the street, but definitely had room for improvement... had trouble with breaking cranks for instance.

Next iteration will be 434, forged crank, H-beam rods, shoot for high 10s CR, the heads cam & intake in the photos.

1gary

Want to add the standard protocall before you do anything to the block is to sonic ck the bores and deck.Then mag it for cracks.As stated these are really old engines with thin wall blocks. Bore and hone with torque plates to stress the block as if heads where torqued on.

By the time you invest in all the above you are deep under water in the value for the engine.Far and away better off just buying a after market block.

Flycaster1977

iTrader: (1)

I like the lt1 idea alot. I would switch to 94-95 wiring just to eliminate the computer chip/tuning issues. The engine is still a sbc with better cooling for the heads. This translates to the possibility of running higher compression. Get the msd opti and you have solved that issue.
There is still a lot of aftermarket support available. Maybe not as much as in 1997 but still available.

I do not think you are better off buying an aftermarket block for either the lt or the 400. Just get em checked by your engine builder. Neither of these blocks is prone to cracking.

Flycaster1977

iTrader: (1)

kid, the 93 actually has a chip like the earlier third gen camaros. Gm changed that in 1994. To tune the 93 you need to physically remove the chip and replace it with a burned one. The 94 and up can be tuned through the aldl cable.

silvvette

I have an 87 iroc vert, with lt1(.30 over) and t5 ; built for cruising and reliability. Driven almost daily for 4 years and happy I did it.

400s are sweet, but depends on what your looking to so stretched vs strip.

HyperFlyer

Decent input, the only problem would be I'm not a light driver all the time. I like to fly and do 100+, so I'm not sure if a t5 would do, the lt1 can take it. So I'll switch over to the drivetrain forum and see what options I have