Inliners International Forums General Discussion Engines clifford intake and holley carb.

I have 1950 pickup with a 216. I picked two 261's and in the early stages of tear down. Just trying get my feet going in the right direction. What cam, should go with Clifford intake and Holley carb.

For a good driver look for cam as follows:
Advertised duration: 210/210 @ 0.050 lift
Lobe seperation: 110 to 112

On a 261 cid engine the idle will sound good and still have good manifold vacuum. The engine should pull to 4500-4800 rpm pretty good. Pay VERY close attention to the ignition curve as that will determine how the engine performs.

What Holley carb do you have? Compression ratio? Exhaust system?
ALL these things need to work together!!!!

Ron

I'm looking at a 390cfm Holley (part# 8007?). I was thinking of 9:1 but, I want engine to run on regular pump gas. The truck will be used to road trip for my son, daughter and myself. I will get a set of Fenton headers, have not thought about rest of exaust system. The truck has a grandma 4-speed and Patricks 3:55 rear end. Any information on how to set up head. Have read that what I take off head face I must recess valves the same. Any ideas on valve grinds and opening up head to breath.

I don't want to rain on your parade but with a 216 ci motor have you considered a Rochester 2GC instead of a Holley 4V? With only a low-revving 216 ci engine those secondaries on the Holley will be just going along for the ride anyway, never really fully opening.

Never hear of the Rochester 2GC. But will start looking into this!! Would appreciate any more info on carb. and any info on cam grind. Thank You Very Much!!!!!

I'll bet you cant run 9:1 comp. with a 235/261. Back in the early '60s you couldnt run the regular gas available then which had to be more than 87 octane.

A 235 headed bored 261 which would be in the upper 8's to one would not tolerated it on regular, too much pinging.

Current 261 ownwers correct me if that dont apply today.

Also TRW (maybe now Clevite) had a TP-115 cam with 228/234 @.050 and .404/.410 lift. good cam but NO ROUGH IDLE (darn it) as installed it had 10 degrees advance for good bottom end(at the expense of top end. It ran good with the stock 'vette triples.

Greetings . . .

What do you think would prevent him from running 9:1? Pump gas is anything you can buy at the filling station no? My wife's Volvo i5 in a V70R has 8.5:1 c/r plus 10 pounds of boost. Runs great on 91 better on 93.

It is interesting to that you say you had issues with 9:1 C/R back in the day. You talking high-test or economy grade?

regards,
stock49

when he said regular pump gas, I thought he said (and meant) regular (87 octane) pump gas.

I could not run the "Regular" grade of pump gas ( 89 octane or so) back in those days (had to buy the 22 cent stuff). Those old sixes with their Recardo(sic) designed combustion chambers were very octane hungry motors, some said they were a copy of an older Mercedes chamber-never researched it though. Never seen another combustion chamber like them before or since-the high comp pistons were really different too (the flattops with a piece of dog poop on them).

Filling station attendants would grin when I asked for a couple of dollars of ethyl for my smooth idling '54 chevy. But it would rattle like a sack of marbles hitting the fan if I didnt.

That old 261's ratio with the '54 235 7.5 to one ratio head actually had less than 8.75, maybe closer to 8.5. Heck the '57 and laters were up to maybe 8.25 and burned low octane, with stock distributor timing. But when you bumped the timing up you wouldnt go back to stock settings.

So maybe it was the higher timing, rather than the compression ratio, but I would not give back the additional snap and response of the advanced timing for the sake of a nickle per gallon difference in price.

I agree I think that advanced timing is as big a culprit as compression ratio.

Your comments about the combustion chamber design are interesting - did you also have run-on after the key was turned off? That could be glowing carbon build up.

Some also worry that gas from the old days was different/better or higher octane then today - from what I have read the difference is or more what fuel engineers call 'sensitivity' then an absolute difference in AKI number:
Bruce Hamiltion's Gasoline FAQ

The pump number or AKI is R+M/2. Today's fuels have as much as a 10 point spread - so today's 87 actually has a higher R then yesterday's leaded stuff (92+82)/2=87 versus (89+85)/2=87. Since the old leaded gas actually had lower R and higher M - they were much less likely to knock under sustained high loads. And is why lead is still used in boats and planes. As I understand it today's gas is formulated with a higher R number to avoid run on - and not so much to prevent knock.

For me I assume that if one is building a hot rod one designs with high test in mind - but doesn't get so crazy that one needs to take Gerry cans out the airfield for AVgas!

regards,
stock49

No run-on, the engine was fresh. Later I ran another bored 261 in a '56 pickup (12 volt starter) with a '56 235 pickup head and based on the past experiance with the other 261, I immediately went to the ethyl gas and max timing (probably more timing yet due to 12 volt starting power), cant say for sure as timing mark was just a ball bearing smashed into the flywheel. I'd just twist the dist and listen for the ping on the road.

Earliest motor was with stock model BC carb, and later motor had the six cyl 'vette stuff, so the later one with its 3.90 rear gear -really felt like a bear- would roll out side-by-side with a 4.10 axle q-jet 350 surburban through 70 mph. Really surprised its owner (me too).

I agree about the lack of need for av gas..hate to think of what it may cost too.

Later,
Ed

Looking to set up my 261 intake system. I have no parts as of yet! Would apprecate thoughts on advantage - disadvantage of single four barrel, single two barrel or 2 two barrels. Also keeping fuel mileage in mind.

Thanks for your time & info,
BL Parrot

Well, here is my nickel's worth: I have a '40 chev convertible with a modified '62 261 in it. Cam, head work, headers, forged pistons, bored .080 over, HEI ignition, etc. Anyway, I originally had a Holly Pro-Jection on it that was an early model and after fighting with it for a couple of years gave up on that. I have since talked to some who have the later units with the O2 sensors and they have been happy with them. After that, since I still had the Clifford 4 barrel manifold on the engine, I decided to try the Holly 390 and was amazed with how nice the engine ran! Another plus was having an electric choke which eliminates cable hookup. After running this setup for a few months, I was getting ready to head to Louisville for the Street Rod Nationals so asked a local Dynomometer service to make a run and do a tune check. (if you are interested, the car is in the "rides" section) They found the carb to be right on the money for my application with no jet changes needed...they did make one minor accelerator cam change. In that configuration, the engine put out 184 HP at the rear wheels at 4600 RPM. I have also built a couple of 261's for other guys and used the complete three carb setup from Tom Langdon with equally good success (plus it looks a lot cooler) Hope this helps. I haven't gotten any fuel mileage numbers from the multiple carb setups but I generally get 16 to 18 MPG on my Chevrolet.

Presten, do you have the cam card on your cam? Can you tell me what was done to the head or who did the head? I like the single carb setup. So for now, it looks like I'm going with the Clifford intake and Holley 390. I think you for your letter, time and info.

BL Parrot