A few months back I bought a 59 stepside Apache it has a stock 235 in it.
Parts I have for it in the house are a 268duration cam from Clifford cam, Fenton dual headers and a fancy triple ace intake from a '54 vet
So, looking for lifters. Do the years matter? The 261 from '55 will fit or nah? I'm under the impression that I need to cram 261 parts inside this 250 because of that intake
What about valves? Is there an "up size" that we can put in the head so it breathes bigger breaths? (I got vortec valves in my amc 258 can we do something like that with the 848 head?)
Any advice otherwise, aside from talking me out of doing this build cause it's fruitless. ima do it out of spite snd have an evil truck
The Vette intake is for a 235 with a very small cam, 24.5 degrees of overlap, and tweaking the carbs will be needed with that cam. All 1937-early 1954 216, 235 and 261 camshafts are steel, and must only use compatible chilled iron (“milk bottle”) tappets. Biggest journal is 2.028". Visual camshaft ID: http://tinyurl.com/3c3obzk Late 1954-55 engines use large journal steel camshafts. Biggest journal is 2.154". 1956-1963 235 & 261 camshafts are cast-iron, and must only use compatible (common) cast-iron tappets. These are hard all over (but softer than the chilled iron’s contact surface). What years show on the cam card?
The Powerglide engine used a 1/16" larger intake valve, will it help? IDK.
I would contact Clifford to see what they recommend for the lifters to go with that cam.
If you have the actual Corvette intake that uses the Carter side draft carbs, contact carbking on this forum to discuss rebuild kits. Do you already have the Vette carbs? If you don't, you're probably better off with a traditional triple that uses downdraft carbs instead of the Corvette triple. With more options, you'll have more success piecing together a matched set of downdraft carbs. With a good progressive linkage setup, you can set it up for reliable normal driving and have the other carbs kick in when you jump on it.
I don't think the 261 differs from the 235 as much as you're expecting it to, so trying to use all the 261 parts you can in your 235 won't do much for performance compared to the 235 parts you already have.
If you've got a real Corvette intake and matching carbs- - - - -sell it to a collector/restorer and you'll make enough money to build a couple of high performance engines. The power gain over a proper sized single carb is minuscule, and the Corvette setup is priced like it's pure gold- - - -not plated! Take anything Clifford tells you with a big grain of salt- - - - -they're long on unsubstantiated claims, and short on facts and figures to back up their "fertilizer". A 268 duration cam needs more compression than an 848 head can make without going to very expensive custom pistons, and the RPM range where the power would be made is at the very top of what the cylinder head is able to flow.
If you want lots of power and RPM, trash the six and install a small block V8. You'll get twice the horsepower gain at less than half the price. Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
"Take anything Clifford tells you with a big grain of salt" X2!
At one time, there was a disclaimer (or "qualifier") from Clifford that said "... when used with other recommended upgrades". Like more CR, CFM, and header...
W/r/t compression: I agree, the cam will drop CCP and low speed torque (and any cam with its intake valve closing point significantly later than the stock cam), some of which will come back with a substantial increase in CR, but this probably mean $$$ pistons. If you're going to use it with stock CR, advancing the cam position (all valves open and close earlier) will help slightly, but the piston may strike the intake valve (the exhaust is safe).
I just spent 10 minutes cleaning up this thread. If y’all can’t keep it civil this thread will go away.
Martin '62 Chevy C-10 Stepside Shortbed (Restomod in progress) '47 Chevy 3100 5 Window (long term project) ‘65 Chevy Biscayne (Emily) ‘39 Dodge Business Coupe (Clarence) “I fought the law and the law won" now I are a retired one! Support those brave men/women who stand the "Thin Blue Line"! Hug a cop! USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)
So Clifford filled out the Howards spec sheet and placed the order. The cam is drop shipped to purchaser. Clifford made a few dollars for middleman (dealer) fees.
What's the deal with the valve springs? Stock is not strong enough?
Last edited by buoymaker; 10/29/20222:52 PM.
"Adding CFM to a truck will only help at engine speeds you don't want to use." "I found there was nothing to gain beyond 400 CFM."
Clifford and JEGs etc. say nothing about that cam. Depending on intake/exhaust bias, duration @ .050, and LSA it may do almost nothing (too mild), or quite bit. Do you have the cam card? Just a guess: 268 is the nominal or lashed duration. Subtract at least 50 degrees for the .050" = 218. Warm LSA 108: IO 26 BTDC, IC 62 ABDC, EO 62 BBDC, EC 26 ATDC, OL 52, OL triangle area 27 "units" Mild LSA 110: IO 24 BTDC, IC 64 ABDC, EO 64 BBDC, EC 24 ATDC, OL 48, OL triangle area 23 "units" Milder LSA 112: IO 22 BTDC, IC 66 ABDC, EO 66 BBDC, EC 22 ATDC, OL 44, OL triangle area 19 "units" Note that the overlap triangle area (when both intake and exhaust valves are partially open) @ 108 is about 50% greater than @ 112.
You haven’t responded to the question posed by member “panic”.
If you want help, actively participate in the conversation please.
Thanks!
Last edited by Gdads51; 11/03/20227:12 PM.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
My point was, why post something like that 5 days after some one replied to your post with a question to try and help you out.
I’m out of this conversation.
~ Dan 1951 Chevy 3 window 3100 Follow this story in the DITY Gallery "My Grandpa Carl's Truck and How it Became Mine" 1966 Chevelle (Wife's Hot Rod) | 2013 Chevy Silverado (Current daily driver) US Army MSG Retired (1977-1998) | Com Fac Maint Lead Tech Retired (1998-2021)
I don’t know what any of that means 🤷ðŸ»â€â™€ï¸
Yep! Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt! There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway Love your enemies and drive 'em nuts!
