You dont lose a total 25% through the transmission. Alot of that is lost through the power transfer to the driveshaft and in the rear end. C4's lose about 25-30 hp typically. My guess by looking at your engine specs is that you arent making 300hp...sorry :shrug:

What brand of dyno did you run on? Some are stingier with the hp numbers than others.

 

I think 20% is pretty standard for an automatic car... The last guy may be on to something. Maybe your not making 300HP

 

well at 20% loss im pretty close. I have seen more mild builds with low rise intakes and non ported iron heads making 280-300 on engine dyno's.

Figured I would have pulled it off with ported cobra heads, and high riser port matched intake and more cam...

 

http://www.mustangandfords.com/techarticles/mufp_0506_vintage_ford_budget_performance/dyno_test.html

This build uses my block and crank and rods.
I make about the same compression and the ported Gt40 heads I use are better than the 351w or 302 stockers they use. Im also using a higher duration/lift cam and better intake...in theory my engine is every bit a 300hp build.

 

I saw your post over at fordmuscle and responded about HP loss. One thing I should also say is that if it is untuned, don't worry about it. With carb tune and timing tune you can get to the 240 mark and maybe more. I remember the first time I had my car tuned after the build I picked up 19 HP on carb tune alone.

 

Yea you are everywhere! Anyways I think your right on that. The only tune that has been done is simply adjusting A/F by sound and kind of playing with timing but not for long. The dyno run was for a baseline not a tune.

I wouldnt mind trying a holley style carb to have more tuning capabilities...

-thanks for the replies, my father has always had
hot rods and mustangs but this is my first personal performance oriented build!



Edit: I just checked timing, it was 8 initial and about 30 total. Now its 10 initial and should make it 32 total...8 was a bit low I think?

 

I did a quicky Desktop Dyno on your motor and, yes, you should be making over 300hp. Not sure what your heads flow so I cant give specific numbers. Your lower than expected numbers are probably from not having the motor tuned properly. As has been mentioned you can pick up a lot of hp with a tune.

 

Cool, I wasnt trying to attack you when you said I prob dont make 300 at the engine but I had researched similar builds alot before I did this engine.

Im thinking that more timing now and possibly even bumping it up to 12 if it runs well at 10 iniital will provide slightly more performance.

 

Its all good, I didnt think that you were attacking me. I was just suprised that it would make that much power. The big cam does that motor alot of good. Good luck with your tuning :thumbsup: The extra timing advance will definitely help you out. Also, is your carb the manual choke or electric choke (1406) variety? 1406's are jetted pretty lean from the factory