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Old 11-02-2014, 02:39 PM   #1
bamafan1
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Clifford performance experience

I have a 1969 c10 stepside I have fully restored. It is an original 250 ci with a 3 speed on the column. I've put about 300 miles on it since a full restoration and drivetrain overhaul. I put 2.5 in drop spindles on the front and 3 in lower springs on the rear. The truck looks and runs great. That being said, improving the 250 a little would be cool. It has a mild Comp cam in it and I'm curious if anyone has any experience with the Clifford stuff. I'm considering the header, intake and Weber 38 carb setup. My concerns are exhaust clearance now that the truck is lowered and overall improvement. I live at 7000 feet in elevation (Colorado), and a lot of people overcarburate here. I appreciate any suggestions.
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Old 11-04-2014, 08:11 PM   #2
bkeith65
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Re: Clifford performance experience

Hey Bama fan. I have a 292 being built by an engine builder right now. I am running dual 38 webers, shorty headers. The head has had extensive work done and is being pulled for more work. It has a mild cam, can't remember specs, but will post when I get build sheet. Initial compression was a tick below 9. Has roller rockers and HE I ignition. Numbers so far...270 hp and 280 tq . Builder wasn't happy with numbers, so is milling head for near 10 compression and reworking head. Extra work being done at no cost! Headers would not seal and were checked on 2 different heads. They had to be welded and machined to fit properly. My understanding is no difference between shorty heanders and full length due to the sequential nature of the I6. I will post more info as it becomes available.
Brian

1968 Camaro 292-muncie m-22
1974 Chevy Nova 350 th350
1972 Chevy C10 confused 305 needs help!!
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Old 11-04-2014, 08:21 PM   #3
leddzepp
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Re: Clifford performance experience

I highly recommend Clifford Performance stuff. I used it on all my Jeep inline sixes, great stuff. I ran their intake, headers, cam, and a Holley 390 carb.
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1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed.

1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck.


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Old 11-04-2014, 08:32 PM   #4
Tinkermc
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Re: Clifford performance experience

On a 258 Jeep inline 6 I also used the company you ask about, 390 Holley , head job,split headers with built in exhaust, sounded so bad a//. Gave some V-8 jeeps a fit, but that was in 1980, I'm old.
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Old 11-14-2014, 12:29 AM   #5
bkeith65
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Re: Clifford performance experience

Hey Bama fan. I have a 292 being built by an engine builder right now. I am running dual 38 webers, shorty headers. The head has had extensive work done and is being pulled for more work. It has a mild cam, can't remember specs, but will post when I get build sheet. Initial compression was a tick below 9. Has roller rockers and HE I ignition. Numbers so far...270 hp and 280 tq . Builder wasn't happy with numbers, so is milling head for near 10 compression and reworking head. Extra work being done at no cost! Headers would not seal and were checked on 2 different heads. They had to be welded and machined to fit properly. My understanding is no difference between shorty heanders and full length due to the sequential nature of the I6. I will post more info as it becomes available.
Brian

Final Numbers
Compression 10 to 1
Horsepower 285
Torque 315


1968 Camaro 292-muncie m-22
1974 Chevy Nova 350 th350
1972 Chevy C10 confused 305 needs help!!
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Old 11-14-2014, 02:05 AM   #6
leddzepp
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Re: Clifford performance experience

Quote:
Originally Posted by bkeith65 View Post
Hey Bama fan. I have a 292 being built by an engine builder right now. I am running dual 38 webers, shorty headers. The head has had extensive work done and is being pulled for more work. It has a mild cam, can't remember specs, but will post when I get build sheet. Initial compression was a tick below 9. Has roller rockers and HE I ignition. Numbers so far...270 hp and 280 tq . Builder wasn't happy with numbers, so is milling head for near 10 compression and reworking head. Extra work being done at no cost! Headers would not seal and were checked on 2 different heads. They had to be welded and machined to fit properly. My understanding is no difference between shorty heanders and full length due to the sequential nature of the I6. I will post more info as it becomes available.
Brian

Final Numbers
Compression 10 to 1
Horsepower 285
Torque 315


1968 Camaro 292-muncie m-22
1974 Chevy Nova 350 th350
1972 Chevy C10 confused 305 needs help!!
__________________
1972 C/10 Cheyenne Super SWB. Restored, loaded, slammed.

1968 C/10 50th Anniversary LWB. Unrestored, stock, daily driver/work truck.


RIP ElJay
RIP 67ChevyRedneck
RIP Grumpy Old Man
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Old 11-14-2014, 10:48 AM   #7
suville
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Re: Clifford performance experience

Quote:
Originally Posted by bkeith65 View Post
Hey Bama fan. I have a 292 being built by an engine builder right now. I am running dual 38 webers, shorty headers. The head has had extensive work done and is being pulled for more work. It has a mild cam, can't remember specs, but will post when I get build sheet. Initial compression was a tick below 9. Has roller rockers and HE I ignition. Numbers so far...270 hp and 280 tq . Builder wasn't happy with numbers, so is milling head for near 10 compression and reworking head. Extra work being done at no cost! Headers would not seal and were checked on 2 different heads. They had to be welded and machined to fit properly. My understanding is no difference between shorty heanders and full length due to the sequential nature of the I6. I will post more info as it becomes available.
Brian

1968 Camaro 292-muncie m-22
1974 Chevy Nova 350 th350
1972 Chevy C10 confused 305 needs help!!

Who is doing your machine and head work and what all have you done to the head? Building a 292 also, would like to compare info .PM me your contact info and lets get together for coffee or ? OK
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Old 11-14-2014, 11:06 AM   #8
Codez67Chevy
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Re: Clifford performance experience

Quote:
Originally Posted by bkeith65 View Post
Hey Bama fan. I have a 292 being built by an engine builder right now. I am running dual 38 webers, shorty headers. The head has had extensive work done and is being pulled for more work. It has a mild cam, can't remember specs, but will post when I get build sheet. Initial compression was a tick below 9. Has roller rockers and HE I ignition. Numbers so far...270 hp and 280 tq . Builder wasn't happy with numbers, so is milling head for near 10 compression and reworking head. Extra work being done at no cost! Headers would not seal and were checked on 2 different heads. They had to be welded and machined to fit properly. My understanding is no difference between shorty heanders and full length due to the sequential nature of the I6. I will post more info as it becomes available.
Brian

Final Numbers
Compression 10 to 1
Horsepower 285
Torque 315


1968 Camaro 292-muncie m-22
1974 Chevy Nova 350 th350
1972 Chevy C10 confused 305 needs help!!
What was the final cost for everything you did?
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93' Toyota pickup 2WD 2dr and 32mpg. Daily driver. 300k+

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Old 11-14-2014, 11:31 AM   #9
slomotion
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Re: Clifford performance experience

The only thing I have to offer is if you continue to have leak problems with the headers go to a cast iron set. A cast iron head and steel headers expand and contract at different rates and this sometimes causes a problem. I put Langdon cast iron ones on my 292 years ago and haven't had a problem since.
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'68 Short C20 Flatbed Dually
w/ 292 4bbl, Langdon cast headers,
and WC T5 trans.

'81 G10 Shorty Van

"Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers

"Under promise, then over achieve."
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Old 11-14-2014, 12:19 PM   #10
nascarguy320
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Re: Clifford performance experience

I just had my 250 6 rebuilt and the shop told me that my engine dyno was at 325 hp and 300ft, im also at 10.5 comp with a 525 lift cam and 60 over bore with bigger valves and head porting. I have the Clifford intake with two 38 weber carbs and shorty headers it runs very nice.
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Old 11-14-2014, 12:23 PM   #11
Cid250
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Re: Clifford performance experience

Quote:
Originally Posted by bamafan1 View Post
I have a 1969 c10 stepside I have fully restored. It is an original 250 ci with a 3 speed on the column. I've put about 300 miles on it since a full restoration and drivetrain overhaul. I put 2.5 in drop spindles on the front and 3 in lower springs on the rear. The truck looks and runs great. That being said, improving the 250 a little would be cool. It has a mild Comp cam in it and I'm curious if anyone has any experience with the Clifford stuff. I'm considering the header, intake and Weber 38 carb setup. My concerns are exhaust clearance now that the truck is lowered and overall improvement. I live at 7000 feet in elevation (Colorado), and a lot of people overcarburate here. I appreciate any suggestions.
Exhaust clearance, Go fore the Llangdons .cast headers.
I have 250ci .C10,1970 mod, and have to get the cast headers.
Clifford parts is ok, but i am not happy With the suport after i got the parts.
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Old 11-14-2014, 12:33 PM   #12
bkeith65
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Talking Re: Clifford performance experience

Good info Slow Mo! Keep it in mind...

Suville- Engine builder is down in CA... Monte at Machine Tech Racing. He specializes in LS builds, but when I went to talk to him, he had a Nissan 6 with an old SCCA history on the dyno....Flying down to CA today to pick up motor from shop and bringing back in Dec... will post pics and dyno video next week. Will pm info...

Codez67- Final cost- fuzzy numbers here..I'll firm them up when I get build sheet...
Scored on block and crank- Had them sitting in shop abandoned- 300 bucks all ready to go.. also threw in high perf clutch and pressure plate!
Carbs 1389.00
Headers 359.00
HEI 180.00
Build 3800 included head work (lump port, milling, porting, larger valves, roller rockers, Monte sourced a steel crank at no cost. break in and tune and dyno)

Soo maybe 6500 total...other incidentals came off my original 230...valve cover, breather, side covers from 12bolt.com.

Pics to follow next week if I remember!!
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Old 11-14-2014, 12:34 PM   #13
bkeith65
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Re: Clifford performance experience

SloMo-on your exhaust...single or dual and why?
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Old 11-14-2014, 02:42 PM   #14
slomotion
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Re: Clifford performance experience

Quote:
Originally Posted by bkeith65 View Post
SloMo-on your exhaust...single or dual and why?
The headers are for the breathing with the 4bbl. The interior of my 292 is bone stock with about 33K miles on it. (Long story about the mileage)
The split manifolds and pipes run down under the cab as duals. I didn't want to cross under the truck with the right side pipe, and I preferred not to have the two exhaust pipes dumping together. Being a dually, there's a lot of open space, but I didn't want the exhaust pipes just hanging out either. The pipes came under the cab pretty close together and didn't leave a lot of room for a pair of mufflers, but one of the guys at the muffler shop came up with a muffler for something that had a 3" inlet, and two 2" outlets. I looked through the muffler from both ends and could see right straight through it. There was no indication of baffles either direction. I asked them to put it on backwards, so now the two 2" pipes from my duals go into one muffler and come out the one 3" end with a downturn behind the cab. The engine breaths well, there's no restrictions, and there's no obnoxious resonance in the cab at any RPM.
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'68 Short C20 Flatbed Dually
w/ 292 4bbl, Langdon cast headers,
and WC T5 trans.

'81 G10 Shorty Van

"Good judgement comes from experience, and a lot of that comes from bad judgement." Will Rogers

"Under promise, then over achieve."
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