Any engine guys here ? Cam shaft question

[Mad4slalom]

Hi , just browsing through some of the engine build paperwork that came with my 72. And wondered if anyone can offer opinion on whether the cam in my motor is mild or a bit lively? Motor was a 73 4 bolt main block , bored +30/1000” flat top 10 to 1 comp pistons . With 2.02 camel hump heads. The pics show some cam grind specs that mean nothing to me , I wonder if anyone engine based can explain a bit more from the lift and duration figures as to what sort of cam it is. Havent driven yet so cant offer any feedback on performance. Seller said it should rev to aprox 6000rpm and similar power to LT1 but without solid lifters.

 

[Oneball]

Looking at the specs for that part number on Comp cams website below. Pretty mild uprated cam, good mid range. Probably pretty good for the road. Might have slightly lumpy idle. Might have low vacuum just after start up.

Xtreme Energy 230/236 Hydraulic Flat Cam for Chevrolet Small Block

Xtreme Energy 230/236 Hydraulic Flat Tappet Cam for Chevy Small Block. Very strong mid-range torque and throttle response, 2200+ stall.

www.compcams.com

pics are a bit fuzzy but those look like 305cu heads not double hump

 

[Mad4slalom]

Looking at the specs for that part number on Comp cams website below. Pretty mild uprated cam, good mid range. Probably pretty good for the road. Might have slightly lumpy idle. Might have low vacuum just after start up.

Xtreme Energy 230/236 Hydraulic Flat Cam for Chevrolet Small Block

Xtreme Energy 230/236 Hydraulic Flat Tappet Cam for Chevy Small Block. Very strong mid-range torque and throttle response, 2200+ stall.

www.compcams.com

View attachment 8622

pics are a bit fuzzy but those look like 305cu heads not double hump

Thanks, it did have a lumpy idle but decided it was mainly because it had been sat for 12weeks and has only been started and stopped a few times and needs a blast. Gave it some carb cleaner and smoother now. It does have slightly slow vacuum at first but improves when revved. The heads have screw in rocker studs and 2.02 inlet valves so was wondering if were LT1 heads, will have to remove covers and check numbers. I have asked the previous owner what heads are too. Thanks for your input

 

[Mad4slalom]

Thanks, it did have a lumpy idle but decided it was mainly because it had been sat for 12weeks and has only been started and stopped a few times and needs a blast. Gave it some carb cleaner and smoother now. It does have slightly slow vacuum at first but improves when revved. The heads have screw in rocker studs and 2.02 inlet valves so was wondering if were LT1 heads, will have to remove covers and check numbers. I have asked the previous owner what heads are too. Thanks for your input

 

[Roscobbc]

Comp Cams Extreme Energy cam - XE274. I see this quite often spec'd on some of the American Vette forums. Very popular cam - and about as far a you'd want to go for street driveability. The important figures in terms of drivability are the 'lift' figures at .050" (50 thou) - these are 230 degrees inlet and 236 degrees exhaust. Quoted figures can be misleading - opening and closing ramps are important - *a faster opening cam* coupled with a cam that closes later means more mixture in the combustion chamber (and therefore more power) Little point having a higher lift cam if the ports are unable to flow enough mixuture - so the importance of efficient cylinder heads can't be overstated. Flat tappet hydraulic is good (no adjusting required) although an equivalent roller cam would help with * above - I would say the comments are correct. Nice 'flat' torque curve with the right heads. This would work well with a 4 speed manual - if an auto you'd need a lower rear end - fit a good dual plane inlet (Edelbrock RPM and 750 DP if a manual) - and with the right heads if should be fun.

 

[Mad4slalom]

Comp Cams Extreme Energy cam - XE274. I see this quite often spec'd on some of the American Vette forums. Very popular cam - and about as far a you'd want to go for street driveability. The important figures in terms of drivability are the 'lift' figures at .050" (50 thou) - these are 230 degrees inlet and 236 degrees exhaust. Flat tappet hydraulic is good (no adjusting required) - I would say the comments are correct. Nice 'flat' torque curve with the right heads. This would work well with a 4 speed manual - if an auto you'd need a lower rear end - a good dual plane inlet (Edelbrock RPM and 750 DP if a manual) - with the right heads if should be fun.

Thanks roscobbc, yes it is a 4 speed with a holley 650 dp and not sure of the manifold. Supposed to rev to 6000 and approx300 gross bhp . Cant wait for first proper drive outside the garden

 

[Roscobbc]

Figure quoted is probably correct - there are some superb aftermarket heads out there that would add another 50+ bhp to that figure - have a word with Andy Maskery, Essex rep he has a set of AFR heads on his 383 stroker engine - works very well on the street.

 

[Mad4slalom]

Figure quoted is probably correct - there are some superb aftermarket heads out there that would add another 50+ bhp to that figure - have a word with Andy Maskery, Essex rep he has a set of AFR heads on his 383 stroker engine - works very well on the street.

Thanks , the previous owner in nystate had body off restored 13 c1/2/and3 vettes over the years so was happy he had done it pretty well which was why I risked buying sight unseen. Should be power enough for me as is , will just be doing a few finishing touches, period seatbelts , pos rechrome front bumper. Hood paint has some sinkage since it was painted so good excuse to swap to an LT1 hood if I can locate one.

 

[Nick B]

I feel your pain brother!

 

[Mad4slalom]

View attachment 8631

View attachment 8631
I feel your pain brother!

Almost 6months since I answered the ad

 

[Forrest Gump]

Figure quoted is probably correct - there are some superb aftermarket heads out there that would add another 50+ bhp to that figure - have a word with Andy Maskery, Essex rep he has a set of AFR heads on his 383 stroker engine - works very well on the street.

I was after mid range torque and the Magnum 270 cam I‘ve used in My 383 stroker is actually smaller than the XE274 cam you have Mad4. I think you’ll be pleased with how it drives, but agree with Ross that it is about as big a cam as you’d want for general street use. And by that he means you will still have plenty of pull without needing to be at 4000 plus rpm all the time.

It’s good that you have the paperwork to confirm what cam you have and tells me that the guy had given thought to how he was building the engine and pass that detail on to you.

I was choosing between two cams often used by well known engine builder David Vizard - a Magnum 270 or a 280. His words were the 270 is all business on the street and the 280 is all business on the strip. (but meaning both would still be street drivers) . Theres plenty of other factors but to generalise you could say your XE274 is roughly in between.
In a dream world I would try several different cams in my car and see which I like best. In reality you pick one and hope you’ve trusted the right advice!

 

[CaptainK]

period seatbelts , pos rechrome front bumper.

Funnily, I want 3 point seatbelts for mine and the bumpers rechromed. Where are you planning to get your seatbelts from? And the re-chroming?

 

[Mad4slalom]

Funnily, I want 3 point seatbelts for mine and the bumpers rechromed. Where are you planning to get your seatbelts from? And the re-chroming?

Seatbelts from corvette kingdom the chrome was going to go to a company in plymouth I had used 40 years ago but they wanted the bumper for 20weeks , and you cant pre book it in, when I read reviews several had stuff get lost and bad results and attitude . So looking elsewhere , someone suggested a co in yate Bristol’

 

[Mad4slalom]

I was after mid range torque and the Magnum 270 cam I‘ve used in My 383 stroker is actually smaller than the XE274 cam you have Mad4. I think you’ll be pleased with how it drives, but agree with Ross that it is about as big a cam as you’d want for general street use. And by that he means you will still have plenty of pull without needing to be at 4000 plus rpm all the time.

It’s good that you have the paperwork to confirm what cam you have and tells me that the guy had given thought to how he was building the engine and pass that detail on to you.

I was choosing between two cams often used by well known engine builder David Vizard - a Magnum 270 or a 280. His words were the 270 is all business on the street and the 280 is all business on the strip. (but meaning both would be street drivers) . Theres plenty of other factors but to generalise you could say your XE274 is roughly in between.
In a dream world I would try several different cams in my car and see which I like best. In reality you pick one and hope you’ve trusted the right advice!

Thanks for your input , the chap in buffalo is very helpful and forthcoming with help and info. We both wrote an article which he put in the two club magazines with persoectives from him the seller and me the buyer. # corvettes of buffalo dec2020 newsletter.

 

[Mad4slalom]

Looking at the specs for that part number on Comp cams website below. Pretty mild uprated cam, good mid range. Probably pretty good for the road. Might have slightly lumpy idle. Might have low vacuum just after start up.

Xtreme Energy 230/236 Hydraulic Flat Cam for Chevrolet Small Block

Xtreme Energy 230/236 Hydraulic Flat Tappet Cam for Chevy Small Block. Very strong mid-range torque and throttle response, 2200+ stall.

www.compcams.com

View attachment 8622

pics are a bit fuzzy but those look like 305cu heads not double hump
[/QUOTEthanks oneball, you are right, looked at the head numbers in my file of paperwork and they seem to be 305 heads (354 434) but cant find any with the 2.02 inlets. There was reference to a company in california that modifies these heads with bigger valves and porting mods.

 

[Oneball]

Sounds like you’ve got a quite nice engine there.

 

[Mad4slalom]

Sounds like you’ve got a quite nice engine there.

I hope so , its killing me waiting to get out on the road though

 

[James Vette]

I viewed a '69 in that colour and it was ace.

 

[CaptainK]

Seatbelts from corvette kingdom the chrome was going to go to a company in plymouth I had used 40 years ago but they wanted the bumper for 20weeks , and you cant pre book it in, when I read reviews several had stuff get lost and bad results and attitude . So looking elsewhere , someone suggested a co in yate Bristol’

Nice one thanks. I took looked at a place in Plymouth for chroming many years back, but decided against it. There is a place near me at Bridgwater area that also does chroming. Thinking of going there and see how it goes. But just busy with house DIY to find the time to do that. Re-chroming costs are very high though I've found. Noticeably more expensive than just getting new bumpers from the states.

 

[Mad4slalom]

Nice one thanks. I took looked at a place in Plymouth for chroming many years back, but decided against it. There is a place near me at Bridgwater area that also does chroming. Thinking of going there and see how it goes. But just busy with house DIY to find the time to do that. Re-chroming costs are very high though I've found. Noticeably more expensive than just getting new bumpers from the states.

I am thinking the same, corvette kingdom do a licensed by GM pattern one , I will ask scott what the quality is like