400 big block? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

the_goat · 05-28-2007, 07:08 PM

What do you guys know about about a 400 big block out of a late 70's trans am?
Anyone have one in one?
Thanks,

Longhorn Man · 05-28-2007, 07:20 PM

probably a 403 olds. Not the first choice for a performance build up, but can make some great power.

eedgell · 05-28-2007, 07:38 PM

Probably a pontiac 400. Good runners, but not as easy to work on as the chevy 400 BB parts arent as good either.

the_goat · 05-28-2007, 07:41 PM

I am asking because I found a 70 c10 shortbed with a rebuilt 400 for 1500 and know nothing about the motor.
Thanks,
John

sodak69c10 · 05-28-2007, 07:46 PM

do you got a picture of the motor i can tell you if it old's pontiac or chevy just with a shot of the intake

the_goat · 05-28-2007, 08:11 PM

Name: 400 bb.JPG
Views: 201
Size: 49.2 KB

Not a great pic but the only one I have

eedgell · 05-28-2007, 08:22 PM

pontiac probably, definately not a chevy BB.

RACINJASON22 · 05-28-2007, 08:44 PM

Looks like Pontiac vintage to me.

I'm a Pontiac lover for sure, parts are more expensive but none the less I like where they make there power, and IMO very respectable power plant for one of our trucks.

One that I have thought about seriously for the future.

The 400 BBC that would have come factory in these trucks would have been a 402 BB chevy engine, another animal all together. OR the 400 SBC that shares all the external demensions of any other yr and vintage SB.

That being said I am a SBC man from the heart but, I am always open to other options and I like to be different.

RJ22...

corn · 05-28-2007, 09:06 PM

Yep thats a pontiac V8. Pretty sure the 350,400 & the 455 were the same style. Not big or small...

EAST SIDE LOW LIFE · 05-28-2007, 09:06 PM

My 50' P/UP has a Trans/Am 400 cu. in it This truck was made for this engine. Lot's of power and not a hint of trouble. I'm happy with the swap.

I'm positive that you will like it.

esll.

Longhorn Man · 05-28-2007, 09:26 PM

i didn't care for the pontiac 350 thatwas in my longhorn when I got it... but it was a worn out POS hittin on 7 1/2 cylinders though.

the_goat · 05-28-2007, 09:43 PM

I have to ask, MPG? 10? It has a 400 trans out of the same trans am, not sure about the rearend ratio.
Thanks

streetstar · 05-28-2007, 10:50 PM

Quote:

Originally Posted by the_goat

I have to ask, MPG? 10? It has a 400 trans out of the same trans am, not sure about the rearend ratio.
Thanks

Thats about all you can expect out of anything with a TH 400 in it for a full size truck.

I have a truck that was originally a 307 vehicle with a t400 -- 10 mpg. When i pulled the mouse motor , i had a performance rebuild done to the tranny and dropped in a 496 stroker big block --- 9 mpg. Same 3:73 rearend. So i got an extra 200-250 hp's for only 1 less mpg

Longhorn Man · 05-28-2007, 10:54 PM

10 - 12 is all you can really count on with any old school motor. If you get more than that... then grin and be happy.
I'm slightly on the lucky side... I'm gettin 12.5 on the freeway with my 425 big block... I hope more since I've tuned it a bit more, but still FAR from dialed in though.

sodak69c10 · 05-28-2007, 10:56 PM

pontiac definately
the valve cover give it away as well as the air gap under the intake

RACINJASON22 · 05-28-2007, 11:22 PM

You may even see a better MPG situation as Longhorn Man does with his caddy engine, since the pontiac makes its power down low and you will get away with higher (highway)gear ratio's numericly lower 3.07 or such and still have decent performance.

One of the reasons this Idea has played around in my head

RJ22...

Texasdeere · 05-28-2007, 11:56 PM

At a glance all the Pontiac engines look the same from the 301, 326, 350, 389, 400, 421, 428, and the 455. I think I remembered those engine sizes right.

I have owned a few Pontiac 400's in the past and I think they are a great engine. A late 70's Pontiac 400 engine should have a "6X" stamped on the two center exhaust ports on each head. Basically they are a long stroke torquey motor. I always thought the 400 or 455 would make a good 1970's pickup truck engine.

GREASEMONKEY72 · 05-29-2007, 06:01 AM

i say go for the truck and have fun with it, the engine will be good fun

rlm316 · 05-29-2007, 08:47 AM

I have been running Pontiacs for over 20 yrs. When they are right they are great running engines. They are touchy on the timing, they need to be really close or they will run hot. I am going to try and post a link to wallace racing, they have a search for block and heads so you will know what you have as far as the engine perfomance goes.http://www.wallaceracing.com/

The great thing about these engines is all the bolt on parts ( heads, intakes, etc,) interchange after 1964. Except the 301, that was kind of a turd. Good luck with this and I think you will love this engine.

05-28-2007, 07:08 PM	#1
the_goat Registered User Join Date: Mar 2007 Location: Carlsbad, Ca Posts: 385	400 big block? What do you guys know about about a 400 big block out of a late 70's trans am? Anyone have one in one? Thanks,

05-28-2007, 07:20 PM	#2
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 400 big block? probably a 403 olds. Not the first choice for a performance build up, but can make some great power.

05-28-2007, 07:38 PM	#3
eedgell It's the air up here Join Date: Mar 2007 Location: Western Colorado Posts: 710	Re: 400 big block? Probably a pontiac 400. Good runners, but not as easy to work on as the chevy 400 BB parts arent as good either. __________________ 1971 cheyenne k10 4 speed np 205 454 BB factory a/c Never drink down stream of the herd! Eric

05-28-2007, 07:41 PM	#4
the_goat Registered User Join Date: Mar 2007 Location: Carlsbad, Ca Posts: 385	Re: 400 big block? I am asking because I found a 70 c10 shortbed with a rebuilt 400 for 1500 and know nothing about the motor. Thanks, John

05-28-2007, 07:46 PM	#5
sodak69c10 Registered User Join Date: Mar 2007 Location: Rapid City, South Dakota Posts: 285	Re: 400 big block? do you got a picture of the motor i can tell you if it old's pontiac or chevy just with a shot of the intake __________________ ,Clint LOUD PIPES SAVE LIVES 69 C-10 short stepside 406 sbc, 02 YAMAHA WR250F, 07 SUZUKI SV650S, 81 Grand Prix 355 sbc, 81 XT 500 YAMAHA

05-28-2007, 08:11 PM	#6
the_goat Registered User Join Date: Mar 2007 Location: Carlsbad, Ca Posts: 385	Re: 400 big block? Not a great pic but the only one I have

05-28-2007, 08:22 PM	#7
eedgell It's the air up here Join Date: Mar 2007 Location: Western Colorado Posts: 710	Re: 400 big block? pontiac probably, definately not a chevy BB. __________________ 1971 cheyenne k10 4 speed np 205 454 BB factory a/c Never drink down stream of the herd! Eric

05-28-2007, 08:44 PM	#8
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: 400 big block? Looks like Pontiac vintage to me. I'm a Pontiac lover for sure, parts are more expensive but none the less I like where they make there power, and IMO very respectable power plant for one of our trucks. One that I have thought about seriously for the future. The 400 BBC that would have come factory in these trucks would have been a 402 BB chevy engine, another animal all together. OR the 400 SBC that shares all the external demensions of any other yr and vintage SB. That being said I am a SBC man from the heart but, I am always open to other options and I like to be different. RJ22... __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR! Last edited by RACINJASON22; 05-28-2007 at 11:19 PM.

05-28-2007, 09:06 PM	#9
corn Registered User Join Date: Dec 2003 Location: here Posts: 5,789	Re: 400 big block? Yep thats a pontiac V8. Pretty sure the 350,400 & the 455 were the same style. Not big or small...

05-28-2007, 09:06 PM	#10
EAST SIDE LOW LIFE Senior Member Join Date: Mar 2007 Location: VANCOUVER ISLAND, B.C., Canada Posts: 1,602	Re: 400 big block? My 50' P/UP has a Trans/Am 400 cu. in it This truck was made for this engine. Lot's of power and not a hint of trouble. I'm happy with the swap. I'm positive that you will like it. esll. __________________ Tomorrow is for doing today's stuff. ************************************* This truck has just the right amount of energy for me! Author: Warren Lake .... (member)

05-28-2007, 09:26 PM	#11
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 400 big block? i didn't care for the pontiac 350 thatwas in my longhorn when I got it... but it was a worn out POS hittin on 7 1/2 cylinders though.

05-28-2007, 09:43 PM	#12
the_goat Registered User Join Date: Mar 2007 Location: Carlsbad, Ca Posts: 385	Re: 400 big block? I have to ask, MPG? 10? It has a 400 trans out of the same trans am, not sure about the rearend ratio. Thanks

05-28-2007, 10:54 PM	#14
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,693	Re: 400 big block? 10 - 12 is all you can really count on with any old school motor. If you get more than that... then grin and be happy. I'm slightly on the lucky side... I'm gettin 12.5 on the freeway with my 425 big block... I hope more since I've tuned it a bit more, but still FAR from dialed in though.

05-28-2007, 10:56 PM	#15
sodak69c10 Registered User Join Date: Mar 2007 Location: Rapid City, South Dakota Posts: 285	Re: 400 big block? pontiac definately the valve cover give it away as well as the air gap under the intake __________________ ,Clint LOUD PIPES SAVE LIVES 69 C-10 short stepside 406 sbc, 02 YAMAHA WR250F, 07 SUZUKI SV650S, 81 Grand Prix 355 sbc, 81 XT 500 YAMAHA Last edited by sodak69c10; 05-28-2007 at 10:57 PM.

05-28-2007, 11:22 PM	#16
RACINJASON22 GEARHEAD Join Date: Jan 2007 Location: CENTRAL,PA Posts: 2,284	Re: 400 big block? You may even see a better MPG situation as Longhorn Man does with his caddy engine, since the pontiac makes its power down low and you will get away with higher (highway)gear ratio's numericly lower 3.07 or such and still have decent performance. One of the reasons this Idea has played around in my head RJ22... __________________ 72 SWB 2WD MY PROJECT 72 LWB 4X4 FUTURE PROJECT SUBSCRIBE HEREBOARD VENDORS HERE NORWOOD MEET SURVIVOR!



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05-28-2007, 11:56 PM	#17
Texasdeere Registered User Join Date: Sep 2006 Location: League City, Texas Posts: 732	Re: 400 big block? At a glance all the Pontiac engines look the same from the 301, 326, 350, 389, 400, 421, 428, and the 455. I think I remembered those engine sizes right. I have owned a few Pontiac 400's in the past and I think they are a great engine. A late 70's Pontiac 400 engine should have a "6X" stamped on the two center exhaust ports on each head. Basically they are a long stroke torquey motor. I always thought the 400 or 455 would make a good 1970's pickup truck engine.

05-29-2007, 06:01 AM	#18
GREASEMONKEY72 Registered User Join Date: Aug 2006 Location: Bakersfield,CA Posts: 7,893	Re: 400 big block? i say go for the truck and have fun with it, the engine will be good fun __________________ -steven Alte Seele S.S. "Allison" '72 C/10 LWB 350SB/TH350 - DD PITBULL IS NOT A CRIME

05-29-2007, 08:47 AM	#19
rlm316 Registered User Join Date: Aug 2006 Location: Woodstown, NJ Posts: 669	Re: 400 big block? I have been running Pontiacs for over 20 yrs. When they are right they are great running engines. They are touchy on the timing, they need to be really close or they will run hot. I am going to try and post a link to wallace racing, they have a search for block and heads so you will know what you have as far as the engine perfomance goes.http://www.wallaceracing.com/ The great thing about these engines is all the bolt on parts ( heads, intakes, etc,) interchange after 1964. Except the 301, that was kind of a turd. Good luck with this and I think you will love this engine.

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