Engine questions.

95GTS · 01-07-2005, 02:28 PM

just got this 67 coupe. It came from the factory with a 289 2V but currently has a 70-up 302 4V. Has the 302 heads, factory Ford 4V intake manifold, a Holley 4V 600 cfm (1850 series?), and a "3/4 race cam" (I have no clue what that means) from I think CompCams. What is the compression of these 302's?

What was the stock hp rating roughly? I've looked at 70 302's specs on the net and the 2V was 220 hp and the 4V was 290 hp. Would that be about right with what this engine was when it was stock? Any guesses what it would be now?

Also, what does a 3/4 race cam mean? I have no specs for it.

Motor has been rebuilt with NO miles on it.

Thoughts??

Rev · 01-07-2005, 05:05 PM

The '67 289 with a 4-V has about 225 hp from the factory. The Hipo version had 271hp The '70 302 with 290 hp was the Boss 302 engine and it was intentionally under rated by the factory. You don't have anything like that. The hp ratings before about 1971 or 1972 were gross hp. More modern engines are rated as "net hp" which is a lower figure than the gross figure.

Long ago, cams were referred to as "3/4 race" for a more streetable cam and "full race" for a not so streetable cam. These terms were never very precise. What you most likely have is a hydraulic lifter flat tappet street cam for some extra power and good driveability.

If you really want to know what kind of power you're getting from that 289, you need to put it on a DynoJet for a rear wheel hp pull. Don't be too surprised though at what the numbers are. from the combo that you describe, probably 175 rwhp or there abouts is what you may get.

Usual prices in Houston for 3 pulls on a DynoJet are about $75. I have an appointment in a week to do mine again. It's really the only objective way to get reliable hp numbers. You can get some idea from drag strip times or G-tech data as well as to your engines power.

Rev

Phillyfanfrombirth · 01-08-2005, 12:49 AM

Does it say "4v" on the head? I think that they ran around 9.5 to 1 compression, of course that will depend on what pistons were put in the engine when it was rebuilt... flat topped, slightly dished, or deep dished... It's been a while since I looked, but I think that the 302 4v heads run around 58cc.

01-07-2005, 02:28 PM	#1
95GTS Git jiggy Join Date: Oct 1999 Location: MO USA Posts: 865	Engine questions. just got this 67 coupe. It came from the factory with a 289 2V but currently has a 70-up 302 4V. Has the 302 heads, factory Ford 4V intake manifold, a Holley 4V 600 cfm (1850 series?), and a "3/4 race cam" (I have no clue what that means) from I think CompCams. What is the compression of these 302's? What was the stock hp rating roughly? I've looked at 70 302's specs on the net and the 2V was 220 hp and the 4V was 290 hp. Would that be about right with what this engine was when it was stock? Any guesses what it would be now? Also, what does a 3/4 race cam mean? I have no specs for it. Motor has been rebuilt with NO miles on it. Thoughts?? __________________ 1967 Mustang Coupe

01-07-2005, 05:05 PM	#2
Rev Registered Member Join Date: Nov 1998 Location: Houston, Tx. Posts: 3,887	Re: Engine questions. The '67 289 with a 4-V has about 225 hp from the factory. The Hipo version had 271hp The '70 302 with 290 hp was the Boss 302 engine and it was intentionally under rated by the factory. You don't have anything like that. The hp ratings before about 1971 or 1972 were gross hp. More modern engines are rated as "net hp" which is a lower figure than the gross figure. Long ago, cams were referred to as "3/4 race" for a more streetable cam and "full race" for a not so streetable cam. These terms were never very precise. What you most likely have is a hydraulic lifter flat tappet street cam for some extra power and good driveability. If you really want to know what kind of power you're getting from that 289, you need to put it on a DynoJet for a rear wheel hp pull. Don't be too surprised though at what the numbers are. from the combo that you describe, probably 175 rwhp or there abouts is what you may get. Usual prices in Houston for 3 pulls on a DynoJet are about $75. I have an appointment in a week to do mine again. It's really the only objective way to get reliable hp numbers. You can get some idea from drag strip times or G-tech data as well as to your engines power. Rev __________________ '66 Coupe, 306, 350-375 HP, C-4, 13.07 e.t., 104.8 mph, 1/4 mi. O.B.C. #2 '66 coupe

01-08-2005, 12:49 AM	#3
Phillyfanfrombirth Registered Member Join Date: Dec 2004 Location: South Central PA Posts: 358	Re: Engine questions. Does it say "4v" on the head? I think that they ran around 9.5 to 1 compression, of course that will depend on what pistons were put in the engine when it was rebuilt... flat topped, slightly dished, or deep dished... It's been a while since I looked, but I think that the 302 4v heads run around 58cc.

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