opinions on 327

[jones]

i have an offer to swap my amc 360 for a 327.the engine will be going into an '84 K20 w/ a 465/205 and 4.10 gearing,and 33-12.5-15. will the flywheel(not flexplate,but ya'll knew that) from a 350 bolt to the 327? i was originally looking for a 350 or 400 to replace the 305.

the truck is used mainly for hauling wood and such.

 

[Stomis]

The 327 is a very solid motor. Its the same block as a 350 but often times has a forged crank from stock. There no reason not to use one. They arent turds like the 305 is (which faces its turdness at the bore).

The one problem you may find with a 327 is the bore/stroke doesnt make as much power down low. Basically in comparison the 327 is to the 350 as a 350 is to a 383.

I saw go for it though and a very good replacement for the 305.

 

[resurrected_jimmy]

I have a 70 K20 with a 327/465/205 4.10's and 35s. I'm very happy with it, makes enough power for me. It is a solid motor and never given me any issues. There are two different 327's out there, small and large journal. I wouldn't trade for a small journal 327. I believe a 305/350 flywheel wil fit the 327.

 

[Mike D]

The large journal 327 had a spin on oil filter from the factory ( 1968 and 1969 ). All the 327's that took a canister oil filter were small journal ( 1961 - 1967 ). The 327's had the ideal bore to stroke ratio. That is why GM brought them back. You can have higher compression without knock.

 

[dyeager535]

Uhh, the bore/stroke *ratio* may be the same, but aren't the bore/stroke completely different on the 5.3's?

 

[Mike D]

I am not positive, however GM is well known for not reinventing the wheel. The 327 had the bore of a 283 engine and the stroke of a 350 engine. This smaller bore longer stroke engine generated greater hp and torque with bigger and bigger cams and high compression piston. The cars were also getting bigger and bigger. Around 1975 emissions requirements required lower compression engines ( from 9.5 - 10.5 to 7.5 - 8.5 ). Gas prices increased and engine performance & fuel economy lowered.
Around 1990 computer designs showed ( GM looked real close at what Ford was doing ) that the 5.3 liter (327) incorporated the ideal bore to stroke design. This meant more efficient combustion, higher compression (without engine knock), more HP and torque, and better fuel economy. Add a roller cam , computer controls, tuned intake, better breathing heads, and a better scavaging exhaust - you get a responsive,fuel efficient power plant.

 

[dyeager535]

Yeah...no.

327 has a 4" bore, same as the 350. If that bore/stroke ratio is good, GM didn't replicate it when the 5.3L was designed. 5.3L is 3.78x3.62" boreXstroke. Closer to the much-maligned 305 bore off the top of my head.

Bore/stroke has less to do with high compression tolerance, as the old 327's that were 10 or 11:1 from the factory still required premium gas, and that was back when people say gas was better than it is now.

Manufacturers are pulling 10:1+ out of engines that run on 87 octane, and my Vortec headed 350 runs 9.6:1 on 87.

Displacement is everything for power, a 350 is a better load hauling motor than a 327.

 

[odin]

Displacement is everything for power, a 350 is a better load hauling motor than a 327.

I agree. In my experience.
Ive built a few 327s and about a dozen 350s over the years and the 350s always were stronger than the 327s. The comparatively short stroke of the 327 always seemed to kill any impressive low end torque.