32 replies to this topic

[yel327]

That’s the article I was looking for.

[Shiney005]

Not sure why they'd want a 400 SBC Laurie?

It must have been a 350. I read this somewhere a long time ago but I can't find that article again for the life of me.  Some people say that once something is on the internet it is online forever. But I dunno. There seems to be so much stuff that was in here in the early 2000's that has disappeared now. 

[yel327]

That 400 is a weird engine. There must have been some logic to it. Chevrolet had the 283, 327 and 396. They added the 427 for certain applications. The 307 replaced the 283 from August 1967 and the 350 eventually replaced the 327 after the 1969 model year. For 1970 model year they introduced the 400 small block and so the 396 wasn't smaller than the biggest small block it was changed to 402ci, and added the 454 to replace the 427.

 

Thus for 1970 model year they had 307, 350, 400, 402 and 454. It is hard to see why they had the 400. Sure it was lighter than the 402 but everything it went into was big, which was mainly C/K trucks and A and B body vehicles. It was only a 2 barrel until 1973, but it was a very torquey engine. The 402 did disappear at the end of 1972 model year and after that the 400 was available as a 4BBL. But for 3 model years they had a 400 and a 402 with the 402 being the performance engine.

[Shiney005]

It only took me two years to find it, and I obviously had my wires crossed as this is 1973.

 

 400 cubic inch motor.jpg   59.32K   1 downloads

[yel327]

It only took me two years to find it, and I obviously had my wires crossed as this is 1973.

400 cubic inch motor.jpg

I’ve had that for years. I even have the full engine number for the engine GMH had in the 350Z. GMH only ever had one or two engines and abandoned the idea in 1973.

It only took me two years to find it, and I obviously had my wires crossed as this is 1973.

400 cubic inch motor.jpg

I’ve had that for years. I even have the full engine number for the engine GMH had in the 350Z. GMH only ever had one or two engines and abandoned the idea in 1973.

[yel327]

Laurie, to put that 400 into context.

 

The engine GMH were using in the 350Z was an LF6, which was a CLK suffix. That is a 1971 engine. It in SAE Gross terms was rated at 255hp @ 4400rpm and 390 lbft @ 2400rpm.

 

Compare that to the new (for HJ) 5.0L with (in SAE gross terms) 250hp @ 5000rpm and 320 lbft @ 3400rpm.

 

With the old HT-HQ 308 being (again is SAE gross terms) 226hp @ 4800rpm and 300 lbft @ 3200rpm (although advertised as 240hp @ 4800rpm and 315 lbft @ 3000 rpm).

 

You can see that with the improved HJ 5.0L it didn't make sense to use that 400, it was hardly worth it.

 

The new (for 1974) LT4 4BBL 400 had a bit more power but GMH had already decided against it. I don't have SAE Gross figures for it, but I have SAE net for both the 1974 LT4 and LF6 for comparison, both are for automatic engines:

 

LF6: 150hp @ 3200rpm, 295lbft @ 2000rpm (in 1971 the LF6 was rated in SAE net at 170hp @ 3400rpm, 325 lbft @ 2000rpm).

LT4: 180hp @ 3800rpm, 290lbft @ 2400rpm.

 

You can see the even more smogged up 1974 4BBL 400 was rated in SAE net not much higher than the 1971 LF6.

[Shiney005]

Yes, I can see why they wouldn't have used it.  I find it amazing that Engineering would have considered it at all that late in the piece.

[yel327]

Yes, I can see why they wouldn't have used it. I find it amazing that Engineering would have considered it at all that late in the piece.

It was for the new Caprice, where it would have been standard. Plus optional where it was optional in HQ, ie Deville, GTS, LS and Monaro (although Monaro was canned prior to HJ release). If they wanted a big torquey engine the only other one in the Chevy stable was the LS4 which was a 454.