do you HAVE to use a high hump cab to run a big-block? - The 1947 - Present Chevrolet & GMC Truck Message Board Network

superchevy · 05-05-2003, 04:08 PM

My 68 cab is a low hump 2wd small block cab. Will I have any problems leaving it as is and putting the 468 in?
SC

Alexis · 05-05-2003, 04:14 PM

I dont think the motor really effects the hump. i think the hump is mainly based on the tranny you run.

Orence1 · 05-05-2003, 04:21 PM

Am almost finished with my 402/350 install. Truck is a 72 Cheyenne LWB 2WD. Was a 350/350 originally. Had no problem with the lower hump. I installed a B&M shifter and there is enough room to put my hand between the tranny and the floor to start the nuts on the attachment bolts. I can't speak for the TH-400 however. Good luck.
Larry

crazy longhorn · 05-05-2003, 05:06 PM

If you have any clearance issues with the BB/400T, it will probably be at the lip(seam) at the bottom of the firewall. I ran a BB Olds/400T, & that was the interferance spot. Good luck,crazyL

still w.i.p '68 · 05-05-2003, 05:47 PM

I havent seen any forseeable problems, with my 454/400,
although it is not totally all hooked up, I used late model mtr mnts, and a factory auto trans crossmember, and its in a '68 swb, that was factory 307/ 3speed....good luck

67cst · 05-05-2003, 07:18 PM

you should be fine, im running a th400 with a low hump, but it have a 73+ auto x member and i had to modify it a bit to work, but i measured a 67-72 tranny xmember and it looked like there was room no sweat

1-PU70 · 05-05-2003, 09:57 PM

Im running a 402 and a 700R4 with a Turbo 350 trans cross member and there is plenty of room in my 70 small hump.

beau396 · 05-05-2003, 10:02 PM

You have to run factory mounts and towers. I am using '72 style mounts and towers in my '67 C10 with a Th400 and small hump and everything clears fine. I am also using a stock auto crossmember.

Longhorn Man · 05-05-2003, 11:32 PM

Mine is pretty close with a caddy 425 and a TH350. Probably an inch or less at the lip that Al mentioned.

hobby67stepside · 05-05-2003, 11:38 PM

With my 454 and M-20 4-speed I've got all kinds of room with low hump.

05-05-2003, 04:08 PM	#1
superchevy Got big-block? Join Date: Jul 2000 Location: Austin, Texas Posts: 2,453	do you HAVE to use a high hump cab to run a big-block? My 68 cab is a low hump 2wd small block cab. Will I have any problems leaving it as is and putting the 468 in? SC __________________ '68 CST SWB factory 396/T400 buddy buckets, a/c, ps, pb '72 Corvette convertible 454/4spd/ac, ps, pb '73 GMC Sierra Grande short wide 454/T400 ps, pb, ac '77 K5 Blazer black on red, 350/T350/NP205 ps, pb, ac all original '78 GMC Sierra Classic short wide 454/T400 ps, pb, ac '72 GMC Sprint SP454. 1 of 38 built. '73 GMC Sprint SP454. 1 of 71 built. '75 GMC Sprint SP454. 1 of 25 built. SOLD! '72 GMC K25 4x4 468/4L80e/NP205 build thread http://67-72chevytrucks.com/vboard/s...23#post4324423 SOLD!'55 Chevy gasser 496/4spd build thread http://67-72chevytrucks.com/vboard/s...96#post4324396

05-05-2003, 05:06 PM	#4
crazy longhorn Fabricate till you "puke" Join Date: Jun 2002 Location: Ill Posts: 9,402	If you have any clearance issues with the BB/400T, it will probably be at the lip(seam) at the bottom of the firewall. I ran a BB Olds/400T, & that was the interferance spot. Good luck,crazyL __________________ 69 longhorn,4" chop,3/5 drop, 1/2 ton suspension/disc brakes,1 1/2" body drop,steel tilt clip, 5.3/Edelbrock rpm intake/600 carb, Hooker streetrod shorties,2 1/2" exhaust/ H pipe/50's Flows , 6 spd Richmond trans,12 bolt/ 3.40 gears....

05-05-2003, 05:47 PM	#5
still w.i.p '68 Dreams are free Join Date: Dec 2002 Location: Hogansville Texas Posts: 546	I havent seen any forseeable problems, with my 454/400, although it is not totally all hooked up, I used late model mtr mnts, and a factory auto trans crossmember, and its in a '68 swb, that was factory 307/ 3speed....good luck __________________ '68 swb fleetside originally w.i.p '68 member since 1-01 w.i.p = ( work in progress )

05-05-2003, 07:18 PM	#6
67cst i love summertime Join Date: Jul 2002 Location: Kelowna BC Posts: 4,302	you should be fine, im running a th400 with a low hump, but it have a 73+ auto x member and i had to modify it a bit to work, but i measured a 67-72 tranny xmember and it looked like there was room no sweat __________________ 1967 shortbox stepside Chevy, 365 hp 327, th400. GLOVE BOX LIGHTS FORSALE, click link for info http://67-72chevytrucks.com/vboard/s...d.php?t=273724

05-05-2003, 09:57 PM	#7
1-PU70 Registered User Join Date: Apr 2000 Location: Bradenton, FL Posts: 1,036	Im running a 402 and a 700R4 with a Turbo 350 trans cross member and there is plenty of room in my 70 small hump. __________________ 1970 CST/10 402,700R4,3:73 posi,AC,PS,PB,TLT,PW,Buckets with heaters

05-05-2003, 04:14 PM	#2
Alexis Member since 2000 Join Date: Dec 2000 Location: Mountain View Ca / Mexico Posts: 7,874	I dont think the motor really effects the hump. i think the hump is mainly based on the tranny you run.

05-05-2003, 04:21 PM	#3
Orence1 Registered User Join Date: Jan 2000 Location: Bothell, WA Posts: 548	Am almost finished with my 402/350 install. Truck is a 72 Cheyenne LWB 2WD. Was a 350/350 originally. Had no problem with the lower hump. I installed a B&M shifter and there is enough room to put my hand between the tranny and the floor to start the nuts on the attachment bolts. I can't speak for the TH-400 however. Good luck. Larry

05-05-2003, 10:02 PM	#8
beau396 Registered User Join Date: Nov 2002 Location: oak harbor wa Posts: 61	You have to run factory mounts and towers. I am using '72 style mounts and towers in my '67 C10 with a Th400 and small hump and everything clears fine. I am also using a stock auto crossmember. __________________ '67 C10 short box fleet side wood bed small rear window frame off restoration. 396BB,Th400, ps, pwr disc 5 lug, posi 3.07, 2000 Suburban 60/40 pwr seats, 2.5" front drop 4" rear, powder coated running gear.

05-05-2003, 11:32 PM	#9
Longhorn Man its all about the +6 inches Join Date: Jan 2001 Location: Hilliard Ohio Posts: 2,690	Mine is pretty close with a caddy 425 and a TH350. Probably an inch or less at the lip that Al mentioned.

05-05-2003, 11:38 PM	#10
hobby67stepside Registered User Join Date: Dec 2001 Location: NW Iowa Posts: 952	With my 454 and M-20 4-speed I've got all kinds of room with low hump.



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