305 big block

[t-bucket]

hi
looking at getting a 78 pontiac grand prix for a doner car but I don't know much about a 305 big block. does it bolt in where a 350 small block would
will it have a turbo 350 tranny why is it a big block any way?? any other info would be appreciated

 

[Dragfink]

A 305 is a Chevy small block, not a big block, and was used as a GM corporate motor...that's probably why it is installed in the Pontiac...physically, a 350 will bolt in, in the same location, but, you may have to swap over things like brackets and pullies, depending on the application...

 

[hotrod preacher]

you may have a non-chevy motor...there was a 4.9 pontiac engine that could be in there...they used a th tranny, but the boltpattern is different...
easy enuf to swap out a chevy motor/tranny combo though...

 

[zzrodder]

They came with a bunch of different engines in 1978, the Buick V6, a 301 Pontiac V8 and the Chevy 305 V8, etc. If your engine is a Chevy 305, any Chevy trans will fit. The Pontiac 301 has a different Bellhousing pattern that is common to Pontiacs, Buicks, Oldsomibles and Cadillacs, though the 350 turbo and 400 tubro trannys were made in that bolt pattern also, and there were some with a dual bolt pattern too.
Some people mistakenly call the Pontiac 301 and other small block Ponchos "big blocks" since they do appear physically larger than a small block Chev.
As far as engine mounts go, anything in that family of cars will fit in there (G body) like Chevy Malibu, Monte Carlo, Olds Cutlass, Buick Regal.

 

[Screamin' Metal]

ZZ is correct....and also the old Pontiac motors were totally interchangeable....pick up a parts interchange book sometimes and look at a 350 and a 455....

 

[42chevy]

I think all Pontiac blocks are externally the same. Meaning don't call a Pontiac 350 a "small block" around hardcore Pontiac guys.

 

[70_boosted]

from my full understanding with pontiacs...the big guns...350,400,455 are all just pontiac blocks. not small not big, just classified as such for the cubic inches. heads swap all around, just changes CR. intakes all match i do believe as well, as well as all the bells and whistles.

my pontiac 400 is equipped with lar ge chambered 350 heads to give my turboed motor a unique combo but the right CR. my 350 was set up with 400 heads and had a nice all motor setup.

im not very familiar with the 301, 389, etc. pontiac motors are beasts for building torque. they are costly to build, but incredibly strong stock motors.

 

[Screamin' Metal]

from my full understanding with pontiacs...the big guns...350,400,455 are all just pontiac blocks. not small not big, just classified as such for the cubic inches. heads swap all around, just changes CR. intakes all match i do believe as well, as well as all the bells and whistles.

my pontiac 400 is equipped with lar ge chambered 350 heads to give my turboed motor a unique combo but the right CR. my 350 was set up with 400 heads and had a nice all motor setup.

im not very familiar with the 301, 389, etc. pontiac motors are beasts for building torque. they are costly to build, but incredibly strong stock motors.

I'm a hardcore Poncho fan....one of my play-prettys is a 421 superduty with 2-4's in a Catalina. Its a factory drag car with a alum. bumper and other alum. goodies on it. Frame is even swiss-cheesed.....[ddd[ddd[[P
I drive it on the street every-once-in-a-while....

 

[PA41]

Pontiac even cut a bank off the 389 and made 4 cylinder for a while in the 60s. It was a 'do it all' block.

The 301 has the dinkiest crank in it--looks like a model T thing. I wouldn't use it for that reason.. Pontiac did turbocharge the 301 in a TA though--maybe they are built heavier.

PA41

 

[TiredIronGRB]

The '78 Grand Am with a V-8 were the SBC 305.

 

[70_boosted]

i had a cousin with the 81 TA 301 turbo, it was...so-so. tho it could have easily been that he was a total tard of a driver, blew the motor up 8 months after buying it. blew it to hell and cant remember what he did but something was half way out the oil pan once it limped home.

 

[70_boosted]

I'm a hardcore Poncho fan....one of my play-prettys is a 421 superduty with 2-4's in a Catalina. Its a factory drag car with a alum. bumper and other alum. goodies on it. Frame is even swiss-cheesed.....[ddd[ddd[[P
I drive it on the street every-once-in-a-while....

the superduty's are quite the prized objects, with what ive talked from poncho fans. after getting my 70 formula, i harshly learn the difference between camaro and firebird for the similar years, tho im glad i decided on the firebird. had a friend with a 76 camaro that talks so much smack but never ran my 400 before i parked it for a overhaul.

pricier to build but def more satisfying

 

[Screamin' Metal]

the superduty's are quite the prized objects, with what ive talked from poncho fans. after getting my 70 formula, i harshly learn the difference between camaro and firebird for the similar years, tho im glad i decided on the firebird. had a friend with a 76 camaro that talks so much smack but never ran my 400 before i parked it for a overhaul.

pricier to build but def more satisfying

Yep, the 400's are a really torquey motor compared to tthe chevys. And there're almost bulletproof when build correctly. Only weak part in the motor are the rods....its a long stroke motor and puts the motor in jeapordy at over 5500 RPM's. RamAir IV or the SuperDuty rods are the way to go....they can spin on up to 6800-7000....with a good steel crank.

 

[RPM]

I'm a hardcore Poncho fan....one of my play-prettys is a 421 superduty with 2-4's in a Catalina. Its a factory drag car with a alum. bumper and other alum. goodies on it. Frame is even swiss-cheesed.....[ddd[ddd[[P
I drive it on the street every-once-in-a-while....

Is that one of the factory Super Stock cars? They didn't make but about 50 of those things. A friend of mine restored one for a museum here a few years back. He said it was worth about $200,000

 

[Screamin' Metal]

Yea Ron, its one of those SS 421 Catalina drag cars....the frontend is so light, you can actually get your finger and push a dent in it without trying....
I light it off about every 6 or 8 months and run it some. After I get my T where I can drive it where-ever I want it.....theres a fella been pestering me to sell the Pontiac to him. His Brother wants my 55 Gasser.
This next year I'm gonna sell my old flathead Indian....my knees and back are shot....someone that'll ride it and take care of it....and I'm gonna sell the Catalina also....gotta make room....
I'm gonna trade the 55 Gasser to a guy for his 32 Coupe, has a blown 302 I built for it about 20 years ago....

 

[Screamin' Metal]

Yea....I used to do the Nostalgia Drag thing with the car sometimes....just to show the car. Its in pristine condition.....the fella wants it for his car collection. At least it'd be pampered....I get attached to these cars....[P

 

[RPM]

The car they did is in this museum http://musclecarmuseum.com/wys.shtml

It is just a few miles from our shop.

 

[Blue Eyed Devil]

one of my play-prettys is a 421 superduty with 2-4's in a Catalina. Its a factory drag car with a alum. bumper and other alum. goodies on it. Frame is even swiss-cheesed.....[ddd[ddd[[P
I drive it on the street every-once-in-a-while....

Let's see some pics...

 

[Screamin' Metal]

You can see it over at UTube @ the 2007 Pontiac Nationals.....

Its funny....I can drive the car.... the best I can get it is 13.5. The fella I let drive it from the shop can run 12.0's all day long without trying....go figure....It can run alot faster than that with the big slicks and the things tuned....I've got it setup stock. Was running 11.75's.

Its got 13.0 to 1 compression, Factory Tunnelram intake with the big Carter carbs, alum long factory headers with factory exhaust cutouts, alum bumper and frontend, swiss cheesed frame, has less than 6000 original miles on it.
When we'd race it, we'd take the hood off....(alum too)....pop on a fiberglass hood with a snorkle scoop on it, take the cleaners off and put the scoop plate on the carbs with a build in aircleaner so we could use the ramming effect of the scoop. Then set up the jets slightly, run some av gas in it diluted of course, throw on some traction bars and some 22x33 slicks....we'd tune for the track by going up or down on the slick sizes, we had about 6 diff sets of tires mounted up.....3 diff sizes with 2 diff compounds...
She'd run a easy low 11 dressed out....close to 12 flat with a good driver sitting stock with the factory cheater slicks...

 

[70_boosted]

Yep, the 400's are a really torquey motor compared to tthe chevys. And there're almost bulletproof when build correctly. Only weak part in the motor are the rods....its a long stroke motor and puts the motor in jeapordy at over 5500 RPM's. RamAir IV or the SuperDuty rods are the way to go....they can spin on up to 6800-7000....with a good steel crank.

witht he availability of h-beam rods, thats almost a guaranteed upgrade. my build has the forged keith black pistons, with h-beam rods...eagles maybe? if your in there rebuilding you might as well upgrade the parts, i snagged brand new rods for 200. plus i fully machined stock nodular crank which many say can easily hold the stress with not over doing the rpms