Let's Talk Inline Perfomance!?

[chevylookin]

Hello forum. Ive only been on here bouta week or so, and everyone here has given me awesome insight! Thank you. I want to open a thread (sorry if it has been done before but I am still trying to master the "search engine" skill) on inline 6 performance.
A quick summary: I own 2 vintage chevy trucks. I have a bone stock 52 standard short bed. I have cleaned it up and I get thumbs up at the shows. Its great for goin to the grocery store once in a while and I think it tops out at 50 mph. Nothing that my wallet could ever consider turning into a daily, but I love it. I also own a 64 C10 short bed fleet. I have owned it since I was 21. I am 32 now. I have bombed it everywhere with its straight 6 and 4 speed granny. I will never part with it.Ive put 40 K on it in 10 years! Maybe the 52 if I really need the cash. This 64 has potential and I want to be rid of the Siverado due to gas prices from hell again, sooooo......
I have put disc brakes and up-ed the rear gears in this 64 to 3:08's for better freeway drivin cuz I wanna make this my daily (again). I love the L6. Its great on fuel consumption and I have plans to do the T5 tranny swap soon. Basically, what Im gettin at, is has anyone done a performance upgrade on their 230-292 for a daily driver? Im talking about lump porting heads, enlarging valves, mid to high performance cams, double singles carbs, single four barrel carbs, or just sticking with a single but doin mild upgrades to boost performance. Kind like when you are trying to get onto the freeway and trying to merge with traffic and just wishin your lil 6 would get up and GO! But also conserving fuel at the same time?
I dunno, I know my lil 230 has has 130ish stock HP and I would guess I bumped it up to 150ish? maybe by putting in HEI and dropping the fanand puttin in an electric? Id like to get it up around 180-200 HP? with the T5 tranny. What are your suggestions from here?
I will be posting pics as soon as I can stop bustin knuckles and start bustin out the camera. Oh yeah, is there really any HP boost from splitting the exhaust? Thanks forum!

[murdoc]

I would love to hear more on this topic as well. I have not heard split exhaust ever doing much in the area of increased HP or gas mileage. Everyone says they do, but i have yet to have seen it. HEI is a must!!! Pertronics works fantastic on my 250. I would love to bring my gears down as well. Did you change the ring and pinion or the entire axle?

[chevylookin]

Yes, I changed the ring and pinion on the rear axle but saved my six lugs, call me old fashioned. The difference was amazing! I used to get shooed out of the carpool lane with the embarrassment of my friend at my side. I would be taching 3000 rpm at geez, must a been 55 mph! Now I tach 3000 around 70! But I want more! Since I split the exhaust and put in the highway gears with the HEI, its a whole new truck! It is not the same truck I bought with farm gears, and points that would wear out! When a put the HEI in and a tonneau cover on, I think the truck had twice as much power and used a 1/3 less gas! No brainer there! But my next process I want to undertake is the camaro T5 swap. I found an '89 camaro with .62-.63? OD with cable driven speedo! I just need to find the S-10 tail and try this swap that everyone is talking about. Im not scred. I love trying this stuff but keep as much of the originality of this truck but make it a dependable daily at the same time.

[murdoc]

congrats man!! I'm really happy for you and your progress, cant wait to see some pics of the truck. I wanna change my gears over too. Could you tell me where you got the ring and pinion to make the swap? I wanna hold onto my six lug rims too. Theres a group you can join here on this forum that are dedicated to six cylinders and the people who love them....

http://67-72chevytrucks.com/vboard/group.php?groupid=9

[ol Curt]

I would buy/borrow , then read this.....
Amazon.com: Chevrolet Inline Six-Cylinder Power...
After having read it, my personal opinion is that if you want to hot rod a six in a truck....it is probably best to think about a 292

[badblu97]

I know somebody will probably chime in as well, but I used these guys for a slant 6 225 in a dart years ago, and they make great stuff!!

http://www.cliffordperformance.net/M...gory_Code=C250

[fleetsidelarry]

I would be concerned that the little 230 may not be able to pull the 3.08s/OD combo, even in a modified state.
you might find your MPG actually suffering.
now a 292 on the other hand.....

you've done mods to make your engine more efficient, anything more (like head mods) may not be worth the gain or the effort.

'course, you could always turbocharge that little booger

[63 & 64 Bowties]

Lots of info/links here:
http://67-72chevytrucks.com/vboard/s...d.php?t=276823

[chevylookin]

To Murdoc:
I had the guys at Unitrax in Anahiem, Ca install the 3:08's in my truck. The carrier had to be replaced. They also had to replace the passenger axle due to wear because I think that is the side that commonly suffers the most due to non-limited slip. They had everything installed in a day and it cost me a lil over 1K. Worth evry penny in my opinion. Call them or find them at www.gounitrax.com
Im sure they have what you are looking for sir.

[chevylookin]

But FleetsideLarry, I've heard mixed reviews about the 292. Although much beefier, it lacks the top end RPM due to larger stroke. My 230 runs like a scalded dog once it gets up to speed on the highway with the 3:08's and I love it! at 70 MPH's (im guessing, cuz I havent re calibrated the speedo yet) its taching well but still, the lil booger has a lot more left! Plenty of power! All I want to do to the 230 is is lump port a stock head, slap it on and put a mild cam in it with some roller rockers and lifters, slap on the OD and go! Whaddya think?

[Heater63]

As ol curt said, buy Santuccis book on hot rodding the L6- it's the "bible".

Yes, the 230-250 will turn more rpms than the long stroke 292.
And you are on the right path with intake lumps, 1.94 intakes/1.6 exhaust, mild cam, Offy intake, 400-500 cfm carb, headers, and HEI.

Tom Lowe did a lot of dyno testing last year on the 250 and 292. go to inliners.org and contact him, he will supply the results for a small donation to the effort.
I built my 292 using those dyno tests.
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[andyh1956]

i think to make the 230-250 head breathe better you cut out the "tunnel" the center head bolt goes through & use a stud & nut in the intake port. the dirt trackers around here about 20 years ago were taking two small block heads & cutting the end cyl off & welding them together. they bolt on & that gives you a crossflow head. don't remember where they got the manifold or if they made it. been away from that stuff for a long time.
andy
p.s. a 235 will fit where the 216 is in your '52. and where a 235 fits a 261 will too!

[Heater63]

Originally Posted by andyh1956

i think to make the 230-250 head breathe better you cut out the "tunnel" the center head bolt goes through & use a stud & nut in the intake port. the dirt trackers around here about 20 years ago were taking two small block heads & cutting the end cyl off & welding them together. they bolt on & that gives you a crossflow head. don't remember where they got the manifold or if they made it. been away from that stuff for a long time.
andy
p.s. a 235 will fit where the 216 is in your '52. and where a 235 fits a 261 will too!

Andy, just removing the intake port head bolt boss, or even reshaping it, has been proven to not have significant effect. What is proven is to remove it (and this can be done with hand tools) and adding "lumps" in the ports. Search Youtube for "lump ports", Tom has a good video on there. Lump kits are about $100. Cheap horsepower.

Yes, you can take 2 aluminum SBC heads, cut off a cylinder, and reweld to make a "Hybrid" head. The racers have done this for years, but it is not cheap or easy. Again, see Santucci's book on Chevy Inline Performance.
Too bad chevy never made a cross flow head. That head is what holds those engines back from being really spectacular.

[murdoc]

Thanks soo much Chevylookin! i'll give the guys a call tomorrow, i have really wanted to do this coversion for some time now.

[andyh1956]

good info on those six cyl heads! i always watched dirt track racing activity from a distance, never got my hands dirty. my neighbor just drug up a '69 or so c60 w/ a 292. the p/o told him it would run but when they raised the hood someone had absconded with the carb. he is going to scrap it, i will see if i can snag the engine before it goes to the cruncher. before i went to afghanistan i traded a Mercedes wagon for a 261 in a '57 school bus. i need to go get it if it is still there. i got a '56 car 235 in the barn just resting. also just installed a 250 in an m715 right before my last cruz. looks like i am six cyl poor & didn't even know it!
andy

[padresag]

Originally Posted by chevylookin

But FleetsideLarry, I've heard mixed reviews about the 292. Although much beefier, it lacks the top end RPM due to larger stroke. My 230 runs like a scalded dog once it gets up to speed on the highway with the 3:08's and I love it! at 70 MPH's (im guessing, cuz I havent re calibrated the speedo yet) its taching well but still, the lil booger has a lot more left! Plenty of power! All I want to do to the 230 is is lump port a stock head, slap it on and put a mild cam in it with some roller rockers and lifters, slap on the OD and go! Whaddya think?

I agree with Larry on the od and 3.08 gearing with a 230-250 eng
ron

[chevylookin]

SO here are some pics after the T5 tranny swap in my 64 SWBF. So far after a week of driving it everyday 60 miles round trip to work, there have been no issues. I love it. Fuel consumption has dropped noticeably but there are issues like you guys have mentioned with the lack of HP in OD. I have recently taken a donor 230 to have it mildly built to see what additional performance I can gain with a cam and lump ported heads and a double 1bbl (possibly a 3 x 1 intake). I like the idea of each intake having its own direct carb, but my concern is, does atomization drop on the end carbs without having a heat source under it or are there ways to compensate for this? I also just like the nostalgia appearance too as apposed to a single 4bbl. I hope my pics come up as this is the first attempt at posting pics. I tried to get under the truck to show the T5 installed. I also have a pic of where my shifter ended up. Not bad I think. Its very functional and very comfortable to shift. I ripped a shifter handle off a 70-something toyota in the junk yard and tried getting a nut welded on to thread onto the original S-10 fork shifter but ultimately got frustrated and just welded the whole thing together, URGH! Shortened the drive shaft about a foot and slapped on a 11" inch (yes, an 11 inch) 26 slpine camaro clutch kit. Im in it for alot more than I hoped. I payed $350 for the recently rebuilt 89 camaro T5, $140 for the donor S-10 T5 with mecanical speedo, $250 for the shortened/balanced/adapted driveline with new u joints, and $130 for the complete new clutch kit. Almost $900 in it but I couldnt be happier! A much better truck to drive and a hell of alot smoother too! Thank you forum for your help!!

[bubba327]

Originally Posted by fleetsidelarry

I would be concerned that the little 230 may not be able to pull the 3.08s/OD combo, even in a modified state.

My 230 (with a TH350) is running with a 3.07 ratio 12 bolt from a 69 with no problems.
I have 235/60/15 cooper cobras (26.1") so that helps a little. No problems at all with power.
But I am adding a offerhauser intake and a Holley 7448 350 2 barrel just for fun.


I have read Leo's book on the 6 cylinder over and over again . I highly recommend it .

[jocko]

chevylookin, I'd say if you're into the swap for $900 and you're done - then you did really well in my book. Congrats, glad that T5 is working out for you.

Was it easy swapping the S10 tail onto the camaro trans or did you pay a trans shop to do it? Just curious. I've heard nightmares about moving shifter location on a Tremec - but swapping the tail housings on T5s seems like it wouldn't be that difficult - so curious what you thought of it or any hiccups you noted in the process. Looks like a nice install.

[chevylookin]

Hey Jocko, the only thing I had paid to get done was the driveline alteration. I called the guys up and they came out and took the measurements and had it modified by the time I got off work and picked it up on my way home. It turned out to be the easiest part of the project when I though it would be the most difficult. The guys over at Drivelines Inc. of Mission Viejo, Ca really know what they are doin.
As for hic-cups, I initially assumed I had a 10.5" clutch behind that 230 so that was the typical clutch kit also for an 89 Camaro. I was surprised when I found out that it was an 11"! So, after a day of searching and alot of help from Rob over at Tops in Anahiem, we got the correct 11" HD clutch for an 89 Camaro the next day. It was an easy install with the only modification to the trans being drilling out the mount holes to 1/2" Easy! Swapped all the parts myself, very straight forward when it came to the tailhousing swaps. I had one Gulp! moment when the oil slinger gear that goes into the internal column connecting the 5th gear fell out upon disassembly and I wasnt sure exactly how it went back in and there are various differences in that area between eachother. The little plastic oil slinger in an S-10 tailhousing is bigger than a camaro's so you cannot fit it so you have to use the one that came with the camaro with the S-10 tailhousing. The shifter plate reassembly was also quite simple. i didnt need three hands at all. Just a couple of beers and some music.

[awbrown]

Some tips on gas milage for you .. I have a 6 261 / now bored and stroked to 300 ci .. as far as intake manifold heat , if you are doing a lot of driving in the winter in a cold climate , you will want it .... if you live in a warm climate I say you can do without it ... also use (if you can ) monojet carbs , these have a double venturi and it atomizes gas better , just like a q jet carb ... if you do a 3 carb manifold make the carbs progresive and heat the center , this in it self will help gas milage ...and use the monojet in the middle ...

If it were I ,I would just go the turbo route and be done with it ... I plan on doint it to my next truck.. I too have a soft spot for 6 cylinders.... Oh , dont worry about horsepower , torque is what is going to get you gas milage and you want it down low , make sure you dont overdo it on cam size...

[chevylookin]

Hey awbrown, thanks for the advice. But what are progressive carbs? I thought that was a term used for vw's like weber carbs and stuff like that. I live in So Cal so I guess heat risers and stuff like that is of little concern since Ive already deleted that when I split the exhuast and if anything, it has improved the fuel consumption. I told the engine builder that I only wanted a mild cam and to keep it as stock idle as possible. thanks for the advice!

[awbrown]

If you run the 3 x1 manifold the linkage makes all carbs operate together, the better way is to have the truck cruise on the center and have the outer ones come in only when you are on the mat ,or 2/3 throttle ... a cam with somewhere between 195-200 duration at .050 would be a good choice , with that small of an engine any bigger would hurt gas milage .comp has a cam part number 61-113-4 that I think would work well ..... the dyno tests on inliners is a good test , just not sure how small of a cam they used and if they pulled the engine down to a point where the normal 6 does most of it's cruising ..... my video on the 261 with a 213@ .050 made more torque below 2400rpm , and we just never thought to pull it any lower to see what it really made as far as max torque .. but it was more than likely around 350 ft lbs , thanks to a 4.220 stroke and a 3.900 bore ......... I will have to see if I can find the photos of the bottom end ,it was h beam rods with a custom piston and a 2" crankpin....

[padresag]

Originally Posted by bubba327

My 230 (with a TH350) is running with a 3.07 ratio 12 bolt from a 69 with no problems.
I have 235/60/15 cooper cobras (26.1") so that helps a little. No problems at all with power.
But I am adding a offerhauser intake and a Holley 7448 350 2 barrel just for fun.


I have read Leo's book on the 6 cylinder over and over again . I highly recommend it .

we were talking with those gears and od which he has with the t5, but I imagine if you are out there on the highway at 60mph, you do not have all of the throttle response that you want
ron

[chevylookin]

Yes Ron, that is true. I really have no (zero) throttle response after 70-75 mph. But given the fact this truck could only go 55 a few months ago, I am happy with the progress. I can drop it into fourth and go 80! Ive had this truck for ten years and never thought I could pass a Porsche in the fast lane!
Im goin to keep messin with this thing til I completely satisfied. If not, I will try the 292, then the 350, and then up to the 454 when gas is $5 + a gallon. Mwah hahahaha!