72 351HO

[jims72]

Was wondering if anyone has personal experiernce with the 351HO engine? I'm considering that cam for a build i'd like to do. Don't hear much about that one, mostly the Boss 351(haven't rulled that one out either) Guess I'm concerned about the smog police and keeping close to stock.....thanks jim

 

[[email protected]]

jim,

no smog police before 75 in CA. don't worry. but that said companies like Comp Cams make good choices. more people will reply.

Jenny

 

[jims72]

jim,

no smog police before 75 in CA. don't worry. but that said companies like Comp Cams make good choices. more people will reply.

Jenny

I got a letter in the mail a while back said their smog sensors in San Jose detected my car was smoking and if I get caught a certain number of time I'd have to take it in for inspection. It does not smoke, use or burn oil what so ever. So I stay the hell away form San Jose. Anyone else get one of these?

 

[hyena429]

jim,

no smog police before 75 in CA. don't worry. but that said companies like Comp Cams make good choices. more people will reply.

Jenny

I got a letter in the mail a while back said their smog sensors in San Jose detected my car was smoking and if I get caught a certain number of time I'd have to take it in for inspection. It does not smoke, use or burn oil what so ever. So I stay the hell away form San Jose. Anyone else get one of these?

Wow...that is messed up {shakes head}...My Rich aunt lives there....And it is the riches town in America.....I will defenatly stay away from there...They do not like our old cars in such towns...Not welcome unless it is some super star driving it. Im sure some one was driving along and turned you in just cause they didn't like your classic.

 

[c9zx]

I owned a Boss 351 and a 351 HO Waaaaayyy back in the day. Both had solid flat tappet cams from the factory. The HO cam had a bit less intake duration, a bit more exhaust duration, little more lift, and less overlap. A lot of progress has been made in camshaft design since 1972. I'd suggest using a modern design cam. Do you want to use solid lifters or hydraulic?

Chuck

 

[jims72]

I owned a Boss 351 and a 351 HO Waaaaayyy back in the day. Both had solid flat tappet cams from the factory. The HO cam had a bit less intake duration, a bit more exhaust duration, little more lift, and less overlap. A lot of progress has been made in camshaft design since 1972. I'd suggest using a modern design cam. Do you want to use solid lifters or hydraulic?

Chuck

Yah, I'd like to go solid if I can keep the lift near or very low half inch area and overlap around 46* or lower.

 

[c9zx]

I don't know what CR or gears you plan on. You might look at something like this http://schneidercams.com/264-74F_351Csolid.aspx Finding a good selection solid flat tappet street/strip cams has become difficult. Schneider will do a "quasi-custom" cam for just a few dollars more. Most of the "big" cam companies only offer one or two. I assume you are going to use pump premium. You need to do a sanity check on effective compression ratio before making a cam choice. Detonation is a terrible thing. Chuck

 

[Wolverine]

I live in SoCal. Working in the traffic industry I was aware of those machines.

In a period of 9 months, I got three notices from the sniffer, and 2 notices because someone reported me.

I also got a finger from an old broad who was stuck behind me at a light.

I enjoyed receiving them all. And the warning don't mean jack....but if they do please let us know.

Was wondering if anyone has personal experiernce with the 351HO engine? I'm considering that cam for a build i'd like to do. Don't hear much about that one, mostly the Boss 351(haven't rulled that one out either) Guess I'm concerned about the smog police and keeping close to stock.....thanks jim

Also, most cam companies do have grinds that match OEM specs. I know a lot of guys puke at the thought of putting an OEM spec'd cam into our motors, but that is what I did.

I have an Isky 351 Boss cam spec, albeit for hydraulic lifters....though that is probably a mistake on my account as I don't have the torque converter or rear end to wind it up...yet. But I do have the closed chambers.

I would investigate building your motor to 1971 specs as 72 and 73 had way more compromises for smog/power. I have a 1971 Service Manual for the motors and can provide whatever info you need. eBay has them occasionally as well $15-20.

 

[mach71351c]

jim,

no smog police before 75 in CA. don't worry. but that said companies like Comp Cams make good choices. more people will reply.

Jenny

I got a letter in the mail a while back said their smog sensors in San Jose detected my car was smoking and if I get caught a certain number of time I'd have to take it in for inspection. It does not smoke, use or burn oil what so ever. So I stay the hell away form San Jose. Anyone else get one of these?

WHAT! You must be kidding. Oh yeah that's rite its flippin California!

 

[marks73]

I hear they call them Smog DOGS for obiouse reasons.

 

[72 R Code]

Was wondering if anyone has personal experiernce with the 351HO engine? I'm considering that cam for a build i'd like to do. Don't hear much about that one, mostly the Boss 351(haven't rulled that one out either) Guess I'm concerned about the smog police and keeping close to stock.....thanks jim

I have one that I have had since new. The Boss and HO heads have adjustable rockers and pushrod guide plates. If you use solid lifters you will need these or have your heads modified.

 

[jims72]

I don't know what CR or gears you plan on. You might look at something like this http://schneidercams.com/264-74F_351Csolid.aspx Finding a good selection solid flat tappet street/strip cams has become difficult. Schneider will do a "quasi-custom" cam for just a few dollars more. Most of the "big" cam companies only offer one or two. I assume you are going to use pump premium. You need to do a sanity check on effective compression ratio before making a cam choice. Detonation is a terrible thing. Chuck

I just sent an email to Schneider about that cam. We'll see what they say. thanks Chuck

I live in SoCal. Working in the traffic industry I was aware of those machines.

In a period of 9 months, I got three notices from the sniffer, and 2 notices because someone reported me.

I also got a finger from an old broad who was stuck behind me at a light.

I enjoyed receiving them all. And the warning don't mean jack....but if they do please let us know.

Was wondering if anyone has personal experiernce with the 351HO engine? I'm considering that cam for a build i'd like to do. Don't hear much about that one, mostly the Boss 351(haven't rulled that one out either) Guess I'm concerned about the smog police and keeping close to stock.....thanks jim

Also, most cam companies do have grinds that match OEM specs. I know a lot of guys puke at the thought of putting an OEM spec'd cam into our motors, but that is what I did.

I have an Isky 351 Boss cam spec, albeit for hydraulic lifters....though that is probably a mistake on my account as I don't have the torque converter or rear end to wind it up...yet. But I do have the closed chambers.

I would investigate building your motor to 1971 specs as 72 and 73 had way more compromises for smog/power. I have a 1971 Service Manual for the motors and can provide whatever info you need. eBay has them occasionally as well $15-20.

That was the only time I ever got a warning. Didn't know they were meaningless. Maybe I'll go back to S J just to piss'm off.

I once had a 270 Isky hyd in it way back in the day. Ran pretty good.

Was wondering if anyone has personal experiernce with the 351HO engine? I'm considering that cam for a build i'd like to do. Don't hear much about that one, mostly the Boss 351(haven't rulled that one out either) Guess I'm concerned about the smog police and keeping close to stock.....thanks jim

I have one that I have had since new. The Boss and HO heads have adjustable rockers and pushrod guide plates. If you use solid lifters you will need these or have your heads modified.

My plan was to replace the valves and modify the heads for adjustable rockers. I like the specs on the 72HO cam, and they're close to a 270Isky I once had in it. I'm looking for smoothe this time, not choppy or anything like that. But it's got to handle cc heads too. We'll see.

 

[c9zx]

The static compression ratio (SCR), rod length, altitude, and cam timing events all contribute to determining Dynamic/Effective compression ratio (ECR). For a pump gas true street engine I'd aim for a ECR of 7.6 -7.9 to leave room for altitude changes and decreasing quality of pump gas. This is a decent ECR calculator http://www.wallaceracing.com/dynamic-cr.php . The same site has many useful calculators that will help get you started in arriving at the SCR and cam combination you want. Let us know what you decide to do. Chuck

 

[1971mach1]

That's the first I've heard of smog sniffers here in San Jose. Do the CHP cars have them?

More likely some Prius owner called the BAR gross poluter hotline to give you a warning.

You smoking too while driving??

I guess I better refrain from punching it with a Prius or CHP behind me!!

Even though smog checks are not required for cars older than 1975, the rules do say you need to have the smog devices installed for the year of the car. Better keep that old snorkle air cleaner and PCV . I doubt they make you pas a sniff test since they are not required, but if the BAR inspector saw smoke at idle could they fail you?

 

[jims72]

The static compression ratio (SCR), rod length, altitude, and cam timing events all contribute to determining Dynamic/Effective compression ratio (ECR). For a pump gas true street engine I'd aim for a ECR of 7.6 -7.9 to leave room for altitude changes and decreasing quality of pump gas. This is a decent ECR calculator http://www.wallaceracing.com/dynamic-cr.php . The same site has many useful calculators that will help get you started in arriving at the SCR and cam combination you want. Let us know what you decide to do. Chuck

Wonderful toys on that site, I gotta go play now. thanks Chuck

That's the first I've heard of smog sniffers here in San Jose. Do the CHP cars have them?

More likely some Prius owner called the BAR gross poluter hotline to give you a warning.

You smoking too while driving??

I guess I better refrain from punching it with a Prius or CHP behind me!!

Even though smog checks are not required for cars older than 1975, the rules do say you need to have the smog devices installed for the year of the car. Better keep that old snorkle air cleaner and PCV . I doubt they make you pas a sniff test since they are not required, but if the BAR inspector saw smoke at idle could they fail you?

I don't know there always seems to be a lot of gray area or misinformation or what ever in this state. I've been followed by cops around here several times in both my stang and 71pu. I guess just cause they're old, both have illegal motors. So far no problems. If I were a cop I could easily make my wages hiding out at a stop lite.

 

[jims72]

The static compression ratio (SCR), rod length, altitude, and cam timing events all contribute to determining Dynamic/Effective compression ratio (ECR). For a pump gas true street engine I'd aim for a ECR of 7.6 -7.9 to leave room for altitude changes and decreasing quality of pump gas. This is a decent ECR calculator http://www.wallaceracing.com/dynamic-cr.php . The same site has many useful calculators that will help get you started in arriving at the SCR and cam combination you want. Let us know what you decide to do. Chuck

I received the specs from Schneider on that 264-74 cam. DCR is 8.14 according to the caculator, but I'm assuming stuff like SCR of 10 for a stock 70cc motor(advertised at 11), 5.778" rod length. I don't know if that's too high at today's gas or not. Gotta research somore.

The static compression ratio (SCR), rod length, altitude, and cam timing events all contribute to determining Dynamic/Effective compression ratio (ECR). For a pump gas true street engine I'd aim for a ECR of 7.6 -7.9 to leave room for altitude changes and decreasing quality of pump gas. This is a decent ECR calculator http://www.wallaceracing.com/dynamic-cr.php . The same site has many useful calculators that will help get you started in arriving at the SCR and cam combination you want. Let us know what you decide to do. Chuck

I received the specs from Schneider on that 264-74 cam. DCR is 8.14 according to the caculator, but I'm assuming stuff like SCR of 10 for a stock 70cc motor(advertised at 11), 5.778" rod length. I don't know if that's too high at today's gas or not. Gotta research somore.

Another thing just occured to me, I don't know if the lash is figured into the spec, .015 lash and IC@62*ABDC

 

[cazsper]

I live in Sunnyvale and I wouldn't worry about cars that are 1975 or older. My brother (and a few friends) use to work for San Jose PD, Sunnyvale PD and CHP. None of them ever bat an eye when I drive by. Even when I drove my My Mustang to test with San Jose PD. My '68 Coupe has a 393w stroker with AFR-205 heads and a 232/240 hydraulic roller cam. Not to mention Hedman mid length headers with 2 1/2 " exhaust and Magnaflow mufflers. I've never had any issues in all of Santa Clara County.

The only thing I think they could possibly get you on is the noise. But again, I've never had any issues.